For this lemon ermine frosting, take a standard ermine frosting and sub any citrus juice you like for the milk. You'll basically end up with a citrus pudding that you then cool and whip butter Into. Day-um, it is good. This recipe makes about 2 1/2 cups of frosting. Double it so you can eat a bunch right out of the bowl. Also, before you whip the butter into it, you could use it as a filling for donuts or cupcakes. You should probably do this and then tell me all about it. If you're using fresh-squeezed citrus, by all means whip in some of the zest to underscore the goodness.
¾cupsugar(to taste, I added an extra 1 1/2 tablespoons this time)
3Tablespoonsall-purpose flour
¾teaspoonsalt(it needs it--but use it to taste)
zest of 2 lemonsoptional but lovely
¼teaspoonvanilla(optional. I used it for a hint of Mellow)
1 ½sticks unsalted buttersoftened
Instructions
Put the juice, sugar, flour and salt into a heavy-bottomed sauce pan.
Heat over medium-high heat, whisking quickly and constantly, until the mixture comes to a boil.
Let boil for about 1 minute, still madly whisking, and then pour through a fine-mesh strainer into a bowl.
Press all of it through the strainer with a flexible rubber or silicone spatula, making sure to scrape any that is sneakily sticking to the underside of the strainer.
Press plastic wrap onto the surface of your pudding (that's what it is, after all), and cool to room-ish temperature in the fridge.
With the paddle attachment, beat the butter until smooth and fluffy.
Once the butter is smooth, beat in the cooled pudding, a bit at a time, scraping the bowl as necessary.
Switch to the whip attachment and whisk the frosting until light and fluffy, about 3 additional minutes.
Notes
I found that the flavor mellowed and matured in the fridge overnight. You can frost your cake immediately, but I'd recommend waiting until the following day to serve it. Also, you can just refrigerate the frosting immediately and then ice and serve your cake the next day. Make sure to re-whip the frosting once it comes to room temperature.VARIATIONS:Sub in an equal amount of any citrus juice for the lemon juice. Key lime works particularly well, but you may want to increase the sugar by a couple of tablespoons since otherwise it will be really puckery.