The recipes for both the peanut brittle and the marshmallow cream make more than you will need for the ice cream. Making either in smaller amounts would be difficult. You will use about half the peanut brittle in the ice cream and maybe 1/3 of the marshmallow cream. Store the cream in the freezer for a few weeks so you can use it in more ice cream or to top tarts.
The Sicilian Gelato base is based loosely on this recipe from Ice Cream Nation.
The recipe for marshmallow cream is based on this one from Chow.com. That recipe is measured in volume, and I haven't converted it yet, so volume it is.
½ozvery dark cocoa powder(I used Black Onyx from Savory Spice Shop)
3Tablespoonscornstarch
4ozsemi-sweet chocolate, chopped fine
1Tablespoonvanilla extract
For the Marshmallow Swirl (measured by volume until I figure out the conversions)
¾cupgranulated sugar
½cuplight corn syrup
¼cupwater
½teaspoonkosher salt
2egg whites
3-4Tablespoonsfreeze-dried coffee(it dissolves really well in the meringue. I used Cafe Bustelo)
1teaspoonvanilla paste or extract
For the Brittle (back to weights again)
8ozdemerara sugar(you can use regular granulated, but the flavor won't be quite as deep)
4ozlight corn syrup(you can use dark if you have it. I didn't)
¼teaspoonkosher salt
¼cupwater
4.5ozsalted peanuts(you can use whatever nut you like, but make sure they're salted)
¼ozbutter(a "pat" of butter)
¼teaspoonbaking soda
Instructions
For the Gelato
Mix the sugar and water together in a heavy sauce pan that is much bigger than you think you need.
Whisk together the milk, cocoa powders and corn starch until well combined. Set aside convenient to the stove.
Put the chopped chocolate and vanilla in a large bowl. Set a fine mesh strainer over the bowl. Set aside.
Bring to a boil over high heat. Cover and let boil for a minute or two.
Uncover, reduce heat to medium/medium-high, and continue cooking the sugar, swirling the pan occasionally, until it caramelizes. You're going for a very dark caramel. It's done when it starts to burn your eyes.
Immediately remove from the heat and pour in the heavy cream all at once. It will bubble up and hiss and spit, so be careful. Add the salt, and stir until the cream is well combined.
Whisk in the milk mixture and heat over medium/medium-high heat until the mixture thickens and comes to a boil. Let boil for about ten seconds, whisking the whole time.
Pour through the strainer. Let the mixture sit for a minute or two to melt the chocolate and then whisk until smooth.
Cool in an ice bath and then chill until the temperature is no higher than 40F. Press plastic wrap directly on top of the base to prevent a skin from forming. The chilled mixture will be almost as thick as pudding, so don't think you did anything wrong.
For the Marshmallow Cream
Combine the sugar, corn syrup, water and salt together in a heavy bottomed sauce pan.
Place the egg whites, coffee and vanilla in the bowl of your stand mixer fitted with the whisk attachment.
Bring the sugar mixture to a boil. Cover and let boil for a minute to wash down any sugar crystals.
Remove the lid and cook over medium to medium-high heat until it reaches 240F.
When the sugar is at about 225F, start whipping the whites on medium speed. Once foamy, increase the speed to high and whip to very soft peaks.
Once the whites are at very soft peaks, the sugar should be at 240F. If you have to err, err on the side of slightly underwhipped whites.
With the mixer on medium, stream the hot sugar mixture into the mixer making sure not to pour the sugar on the whisk. Pour down the inside of the bowl.
Whip on high speed for about 8 minutes, until cooled to room temperature.
Scrape into a gallon zip-top bag or large pastry bag and refrigerate or freeze until ready to use.
For the Brittle
Line a half-sheet pan with Silpat (or spray with pan spray). Set on a cooling rack convenient to the stove.
Spray an offset spatula with pan spray. Set aside.
In a large, heavy-bottomed sauce pan,bring the sugar, corn syrup, salt and water to a boil.
Cover and let boil for a minute or two to wash down any sugar crystals.
Uncover and continue to cook until the mixture reaches 265F.
Pour in the nuts and salt, and stir well.
Cook, stirring constantly, until the mixture reaches 315F.
Immediately remove from the heat and stir in the baking soda. It will foam up like shaving cream.
Pour onto the waiting sheet pan and spread out a bit with the offset spatula and let cool completely.
Putting It Together
Remove the marshmallow cream from the freezer so it will be easier to pipe.
Break up about half the peanut brittle into small pieces. You'll have about a cup of brittle.
Churn your gelato according to manufacturer's instructions until it is the consistency of soft serve ice cream, about 25 minutes for me.
While the gelato is churning, snip the tip off your zip-top bag (or use a round tip) to pipe some of the marshmallow cream in the bottom of your container.
Thoroughly fold the brittle into the gelato and layer on about 1/3 of the mixture on top of the marshmallow. Pipe on some more marshmallow cream.
Spread on another third of the gelato, pipe on some more marshmallow cream and finish with the last of the gelato.
You can add a few pieces of brittle to the top if you want.
Press plastic wrap directly on the surface of the gelato and freeze for several hours or overnight.
This gelato stays nice and scoopable, even straight from the freezer.