Ermine frosting, also known as boiled milk frosting or flour frosting, is a silky, lightly sweetened frosting that's cooked on the stovetop. Its mild, buttery flavor is the perfect finishing touch for your next batch of cupcakes.Adapted from: Wilton's Easy Ermine Frosting
In a saucepan over medium heat, add sugar, flour, and salt. Whisk in milk and continue whisking until smooth.
Cook over medium heat for about 5 to 7 minutes, whisking frequently, until mixture looks very thick (like sweetened condensed milk consistency). Remove from heat.
Transfer mixture to a bowl. Press plastic wrap over the top of the mixture and up the sides of the bowl to prevent a skin from forming. Allow mixture to cool completely to room temperature, about an hour. (To speed up cooling, transfer to the refrigerator, but don't allow it to go below room temperature. Mixture will solidify and become difficult to work with.)
Once flour mixture has cooled, add room temperature butter to a large bowl and beat with a hand mixer (or a stand mixer) until light and fluffy, about 2 to 3 minutes.
Add your cooled flour mixture, 1 tablespoon at a time, to the whipped butter and beat until smooth, scraping the sides of the bowl frequently. Continue until all of your flour mixture has been incorporated. (If your flour mixture is even a little warm it will melt the butter and ruin the frosting. Flour mixture must be room temperature, not warm, for this step).
Add vanilla extract and mix to combine. Frosting should be silky smooth with a whipped texture.
Pipe or spread frosting with a knife onto cupcakes and serve.
Notes
Recipe makes about 2.5 cups of frosting - enough to frost 15 cupcakes, a 6-inch round layer cake, or a thin coating on a 9x13 cake. Recipe can easily be doubled or tripled.
Ermine frosting melts at high temperatures, around 90 to 95 degrees Fahrenheit. If you live in a tropical/humid environment, I suggest storing frosted cake/cupcakes in the refrigerator.
Ermine frosted baked goods can be stored at room temperature for up to six hours after frosting, and otherwise need to be stored in the refrigerator. Frosting will keep for up to 1 week in the refrigerator or 3 months in the freezer.
Food coloring can be added in along with vanilla extract if desired.
Vanilla extract can be substituted with half the amount of peppermint or almond extract.