When you mix boiled milk, flour, sugar, and butter with butter, you get ermine frosting, which is very creamy. For red velvet cakes and cupcakes, this whipped buttercream is the best choice because it tastes great and isn't as sweet as regular buttercream.
– 1 cup granulated sugar (200 grams)– ¼ cup all-purpose flour spooned & leveled (32 grams)– ¼ teaspoon salt– 1 cup whole milk (240 ml)– 1 cup unsalted butter softened (230 grams)– 1 ½ teaspoons pure vanilla extract
Put the salt, flour, and granulated sugar in a medium saucepan and mix them together with a whisk. Add the milk slowly while whisking all the time until the mixture is smooth.
Cook the saucepan over medium heat, stirring often, until the paste is thick and smooth (almost like custard). I recommend scraping the pan's bottom and sides several times while cooking with a rubber spatula. This step may take 15 minutes, so be patient.
Remove mixture from heat and place in large heat-safe bowl. Put plastic wrap directly on the surface to prevent skin formation and let it cool to room temperature. For faster processing, refrigerate the mixture. It should be room temperature when added to butter.
Put softened butter in a stand mixer bowl with the paddle attachment or a large handheld mixer bowl. Beat butter for 4–5 minutes to make it fluffy. On medium speed, add one heaping tablespoon of cooked flour mixture at a time to the mixer and mix until fully combined.
After adding all of the cooked flour mixture, add the vanilla extract and mix for 2–3 more minutes on medium speed until the frosting is thickened and creamy. The finished mixture should resemble whipped cream. Air bubbles can be removed with a rubber spatula.