It’s May, and you know what that means: Burger Month! This year, I’ve pulled out all the stops to make an epic onion burger. Onion jam, caramelized onion cheese, onion in the patties, pickled red onions. So much onion packed into a fantastic double smashed burger package.

Some of the components are homemade, and others are storebought. I’ll let you know how to make all the homemade parts and also give you substitutes if you’d prefer to just focus on the burgers.

If you’re an onion fan, I implore you to give this onion burger recipe a try.

And if burgers are your love language, you can find all my epic burger recipes in one place. Thanks so much for being here!

large burger with pickled onions and lettuce on a wooden board.

Please watch my onion burgers recipe web story here.

Why You Need to Make This Burger

If you like onions–LOVE onions–here’s why you need to make this burger:

Even though it is Super Oniony, most of the onions are slow-cooked and/or caramelized, and the red onions are pickled.

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This means you get deep, rich, sweet onion flavor without all that sharp bite.

And the pickled red onions give a nice, bright, sweet-sour crunch that really compliments the rest.

The burgers have onions soup mix mixed right in, along with Worcestershire and fish sauce for all the meaty, umami goodness you could want, and that rich beef flavor shines through despite all the layers of onion flavor.

This burger, if I do say so myself, is well-balanced and Lovely!

And it’s not so mammoth that you can’t pick it up and eat it with your hands as God intended.

How To Make

Here are all the components.

A close up of a cheeseburger with all the components labled with arrows pointing to each component.

Homemade Components:

  • all-beef patties
  • onion jam (you could also go with bacon jam)
  • pickled onions

Storebought Components:

  • caramelized onion cheddar
  • caramelized onion mustard
  • onion rolls
  • red leaf lettuce

What in the Heck is a Cheese Skirt?

You know how when you cook a burger patty on one side, flip it over, let it cook, and then during the last couple of minutes, you slap a piece of cheese on it, put a lid on it, and let it melt onto your patty?

Well, some of that cheese will inevitably make its way onto the surface of your cast iron pan, making a ring of cheese around your burger.

If you leave the cheese to sizzle for enough time for it to start to caramelize, and then you scrape the burger and the surrounding cheese out of the pan and put it on your bun, well.

The crunchy bits of cheese will sometimes stick out from the burger, or maybe flop over, or both.

That, my friends, is a cheese skirt, and if you love crispy cheese, it’s a must-have on a smashed burger.

You can see the “cheese skirt” forming in this video clip.

If you’re not a crunchy cheese fan, you can put the cheese on the patties after they’re completely cooked and let the cheese melt naturally from the heat of the burger.

Either way, it’ll be delicious.

But, given the choice, I’m a cheese skirt gal!

Ingredients, Substitutions, and Shortcuts

Here’s a list of all the ingredients you’ll need for making the burger patties:

  • 80/20 ground beef: You can sub a leaner mix, but in a smashed burger, you need that extra fat for juiciness. But you could use 85/15
  • fish sauce: If you don’t have/don’t like fish sauce, use soy sauce. You won’t be able to taste either, it just brings out extra meatiness in the burgers
  • Worcestershire sauce: Again, adds meatiness and amps up the beef flavor. Feel free to use all fish sauce or all Worcestershire if you don’t have both
  • dry onion soup mix: 2-3 Tablespoons. Use any version of dried onion soup mix you like: French onion, onion-beef, mushroom-onion, etc. You can technically leave this out, but it does add even more onion flavor to the mix. Note that many onion soup mixes are NOT gluten-free, so if you’re planning on making this to put on a gluten-free bun, check your labels.
  • salt: don’t mix the salt into the burger meat. Save it to sprinkle on 1 side of each pattie as they’re cooking

Ingredients for the Onion Jam:

  • fat: I used bacon fat. You can also use oil, butter, or a mixture of the two
  • sweet onions: Technically, you may use any onions you like here, but if you’re making jam, it makes sense to use the sweetest onions you can find. Walla Walla or Vidalia both work great, but any onion labeled “sweet” will be fine
  • salt: You won’t need much. Add about 1/4 teaspoon at the beginning of cooking and then taste at the end and add a pinch more if necessary
  • pepper: A few grinds of whole peppercorns for best flavor
  • onion soup mix: Another 2-3 Tablespoons from the same packet you used for the beef. Adds more onion flavor and aids in thickening as well
  • water: Since this isn’t a caramelized onion jam, simmer the onions together with the fat, salt, pepper, soup mix and instant coffee (below). This allows the onions to soften in about 10 minutes rather than slowly caramelizing them for an hour or so
  • instant coffee: Provides backbone and the merest hint of bitterness to the jam. It also deepens all the flavors. You can also use a shot of espresso if you have an espresso maker or about 1/4 cup of strong, brewed coffee
  • brown sugar: The onions actually provide a nice bit of sweetness, so the recipe calls for only 1/4 cup of brown sugar. You can substitute maple syrup, granulated sugar, Bocha Sweet to keep it sugar-free, honey, etc
  • vinegar: I use Steen’s Cane Vinegar, which is kind of like a cross between red wine vinegar and balsamic, but any vinegar will do. Use balsamic if you like for an extra bit of sweetener
  • Worcestershire sauce: Adds more depth of flavor and some umami, lip-smacking goodness

Shortcut: You can buy onion jam at some gourmet stores. Or just caramelize some onions and use those.

Ingredients for the Pickled Red Onions:

  • red onions: These are preferred for their bite and of course their beautiful color
  • granulated sugar: You may use brown sugar, but the color won’t be as brilliantly pink
  • water:
  • vinegar: I use a mixture of about 1/2 water and 1/2 vinegar. White vinegar, apple cider vinegar, and red wine vinegar will all work
  • salt: A heavy pinch will do

The Rest:

  • caramelized onion cheese (I purchased mine at Wegman’s)
  • caramelized onion mustard (Ditto, but aso available through Amazon)
  • red leaf lettuce (or your favorite lettuce)
  • onion rolls (Brioche rolls would be nice here, but they are super-rich and the burger is already rich with onions. Or use regular hamburger buns or bun-sized English muffins)


A burger on a wooden board with a jar of mustard and one of onion jam.

You can make the onion jam and the pickled red onions a few days beforehand.

Onion Jam

  1. Dice onions.
  2. Heat a large pan, then add your fat and let melt or get hot (depending on what type of fat you’re using)
  3. Add onions, salt, pepper, soup mix, water, and instant coffee to the pan.
  4. Bring to a boil, put a lid on it, reduce the heat and simmer for 10 minutes.
  5. Remove the lid, add the brown sugar, vinegar, and Worcestershire sauce.
  6. Simmer over medium-low heat until very thick and jammy, about 45 minutes-an hour.
  7. Taste and add a pinch more salt if necessary.
  8. Cool, cover, and refrigerate until ready to use. Jam will keep in the fridge for a good couple of weeks.

Make the pickled onions at least 24 hours before you plan to make your burgers.

  1. Peel and slice the onions very thinly.
  2. Layer into a heat-safe glass jar.
  3. Add sugar, water, vinegar, and salt to a saucepan.
  4. Bring to a boil and let boil for 30 seconds.
  5. Pour over the onions to cover.
  6. Cool, cover, and refrigerate for at least 24 hours. The flavor just gets better the longer you let them sit.
  7. Onions will keep in the fridge for a couple of weeks.

On Burger Day

Buns: slice horizontally (if not pre-sliced), brush cut sides with a little melted butter or bacon fat, and broil, cut-sides-up, until golden brown. Then set aside.

Cheese, Mustard, Pickled Onions, Onion Jam: grab ’em and have all of them ready to go.

Lettuce: If not pre-washed, rinse under cold running water and spin dry. If you don’t have a salad spinner, flatten leaves as much as possible and roll them up in paper towel or a lint-free kitchen towel. Place in fridge until you’re ready to build your burgers

For the Patties

  1. Mix up all the ingredients for the patties.
  2. Divide the mix into 8 pieces, about 2 oz apiece, and roll them into balls.
  3. Heat a large griddle or cast-iron skillet over medium-high heat (you may have to turn it down after the first couple of patties)

Onion Burger Q & A

Is this like an Oklahoma Onion Burger?

They share the same DNA, but this burger has more toppings and the patties are made differently. For an Oklahoma onion burger, you smash thinly sliced raw onions right into the patties, cooking on both sides so the onions caramelize where they touch the pan.

Can I easily make this gluten-free?

Check your onion soup mix to make sure it’s gluten-free. Otherwise, all other components are naturally gluten-free as written. Of course, use your favorite storebought or homemade gluten-free buns.

What if I don’t need to make 4 burgers at once?

The “pattied up” meat will be fine in the fridge, well-covered, for 2 days, so you can make the extra burgers later. You can also cook them all at the same time, layer them up as doubles, and chill. Then when you want a burger, just microwave your double cheeseburger patties until hot and build your extra burgers within 5-7 days. For food safety, make sure you reheat to at least 165F for 15 seconds.

Equipment You May Need

For making smashed burgers, it’s best to have a heavy-duty, metal spatula to do the smashing. After the initial smash, you can use the spatula to press the edges out even thinner for maximum, crispy meat goodness.

I usually cook my burgers in a well-seasoned 12″ cast iron pan, 2 patties at a time.

And that’s pretty much it for equipment, unless you want to weigh your patties out like I do. In that case:

This is the scale I use, love, and recommend. If you’re unsure, please read my post about how to use a food scale.

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Tips for Success

No need to form patties with your meat. Just round the meat into balls. They’ll magically turn into patties when you smash them out on the pan.

Ideally, your burgers should be so thin that they’ll cook in a total of about 2 1/2 minutes. 1 1/2 minutes on 1 side and another minute on the other. Once you flip your burgers, add the cheese and put a lid over them. You burgers will be done just about the time you have a nice cheese skirt around your patties.

A Note About Styling

A large onion burger on a wooden board.

The burger I shot for the “hero image” for this post took me a long time to build to look how I wanted it to.

Do not worry if your burger isn’t Camera Ready.

Trust me, it will be more than mouth-and-stomach-ready!

Take a look at these 3 images.

3 images of an onion burger, 1 thrown together, 1 styled and shot with a phone camera, and the fully styled burger shot with a DLSR camera.

The first is the burger I made for us to just taste all the components together. It won’t win any beauty awards, but it served as “proof of concept.”

The second is the fully styled burger shot quickly with my phone, and the third is the fully styled, lit, shot, and edited “hero” burger.

So just because a burger isn’t billboard-gorgeous doesn’t mean it isn’t epic!

Serving Suggestions

There is nothing wrong with pounding down this onion burger all by itself, or maybe with a side of chips. Sometimes a burger can just stand on its own.

But, if you’re looking for side dishes, it’s hard to say no to some German potato salad or homemade curly fries.

If you’re looking for more versions of smashed burgers, try my smashed bacon double cheeseburger, smashed Reuben burger, or my double bacon bbq burger.


5 golden stars for rating recipes
A large onion burger on a wooden board.

The Epic Onion Burger Recipe

Jennifer Field
This epic onion burger recipe features 2-2 oz smashed patties smothered in caramelized onion cheese, pickled red onions, onion jam, and caramelized onion mustard all nestled onto red leaf lettuce in a toasted onion roll. More onions per square inch than any other burger! (probably)
5 from 2 votes
Tried this recipe?Please give it a star rating!
Prep Time 20 minutes
Cook Time 20 minutes
Total Time 40 minutes
Course Burger Recipes
Cuisine American
Servings 4 epic burgers
Calories 740 kcal


For the Onion Jam

  • 2 Tablespoons bacon fat
  • 2 large sweet onions diced
  • salt and pepper to taste
  • 2-3 Tablespoons onion soup mix
  • 2 teaspoons instant coffee
  • ¼ cup water
  • ¼ cup dark brown sugar
  • ¼ cup vinegar
  • 2 Tablespoons Worcestershire sauce

For the Pickled Onions

  • 1 large red onion peeled and sliced very thinly
  • ½ cup water
  • ½ cup vinegar
  • 1 cup sugar
  • heavy pinch of salt

For the Patties

  • 1 pound 80/20 ground chuck
  • 1 Tablespoon fish sauce
  • 1 Tablespoon Worcestershire sauce
  • 2 Tablespoons onion soup mix
  • salt to taste (when ready to cook)

The Rest

  • 8 slices caramelized onion cheddar
  • ½ cup caramelized onion mustard
  • 8 leaves leaf lettuce rinsed, dried, and chilled
  • 4 onion rolls split
  • a little butter or bacon fat


  • For the Onion Jam
  • Heat a large pan over medium heat.
  • Add the fat, and then the onions.
  • Stir for a couple of minutes, then add salt, pepper, the onion soup mix, water, and instant coffee.
  • Give it another stir, bring it up to a boil, put on the lid, and simmer over medium heat for 10 minutes.
  • After 10 minutes, remove the lid and stir in the brown sugar, vinegar, and Worcestershire sauce. Cook over medium-low until most of the liquid has evaporated out and the mixture is jammy.
  • Taste and add a touch more salt if necessary.
  • Cool, then cover and store in the fridge for up to 2 weeks.
  • For the Pickled Red Onions
  • Pack the siced onions pretty tightly into a jar or other glass container.
  • Place water, vinegar, sugar and salt in a pan, and bring to a boil.
  • Boil for 10 seconds or so, making sure all the sugar has dissolved.
  • Pour over the onions to submerge (you may have extra brine).
  • Cool, cover and chill.
  • Store in the fridge for up to 2 weeks.
  • For the Patties
  • Evenly mix all the patty ingredients except for the salt and pepper.
  • Form into 8 balls about 2 oz each.
  • Cover and refrigerate until ready to cook (up to 2 days).
  • Time to Make The Burgers!
  • Grab the lettuce, buns, mustard, onion jam, pickled onions, cheese, and burger mix. Also grab a little butter or bacon fat from the fridge.
  • Slice the buns horizontally. Spread the cut sides with a little melted butter or bacon fat, and broil until golden brown. Don't toast, because you don't want them crisp on both sides, just the cut sides.
  • Spread about 2 Tablespoons onion jam on the bottom buns.
  • Spread about 2 Tablespoons caramelized onion mustard on the top buns.
  • Place 2 leaves of lettuce on top of the bacon jam. That's where you'll put your burger patties once cooked.
  • Heat your skillet or griddle over medium-high heat.
  • Place 2 balls of burger mix in the pan, several inches apart.
  • Smash them down firmly all around to flatten. Further thin out the edges with the edge of your spatula for maximum crispy-edged goodness.
  • Cook about 1 1/2 minutes on 1 side.
  • Salt the patty before scraping up and flipping.
  • Once flipped, add a piece of cheese on top of each patty, then cover the pan with a lid.
  • Cook for about 1 minute, covered.
  • Scrape 1 patty and surrounding "cheese skirt" up and place on the lettuce.
  • Top with a healthy amount of pickled onions and then add the second burger on top.
  • Top with the mustard-covered top bun.
  • Repeat until all 4 burgers are done.
  • Devour while patties are hot.

Did You Make Any Changes?


Feel free to make these as "regular" 4 oz burgers. In that case, form into patties about 4 1/2" across, and cook for about 5 minutes on 1 side and 3-4 on the other. Top with 1 or 2 slices of cheese and melt with the lid on or just place the patty directly on the bun. There's no real wrong way!
Other substitutions: use your favorite mustard in place of the onion mustard. Spread with bacon jam or even pepper jelly as opposed to onion jam.
Use brioche buns, potato rolls, Kaiser rolls, etc if you cannot find onion rolls.
No matter how you make them, enjoy every bite!
You can also cook the burger patties, cool and refrigerate to reheat within 2-3 days. Then you can go all-out with the toppings as written, or do your own thing!


Serving: 1gCalories: 740kcalCarbohydrates: 104gProtein: 18gFat: 29gSaturated Fat: 16gPolyunsaturated Fat: 10gTrans Fat: 1gCholesterol: 84mgSodium: 1886mgFiber: 5gSugar: 66g
Keyword Burger recipe, onion burger, smashed onion burger
Did you make this recipe?Please tell us what you loved!

Thanks for spending some time with me today.

Can’t wait for you to try this onion burger. Lord, it’s good!

Take care, and have a lovely day.

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