Red Velvet Vanilla Frosting from Magnolia Bakery

6 tablespoons all-purpose flour
2 cups milk
2 cups (4 sticks) unsalted butter, softened
2 cups sugar
2 teaspoons vanilla extract

In a medium-size saucepan, whisk the flour into the milk until smooth. Place over medium heat and, stirring constantly, cook until the mixture becomes very thick and begins to bubble, 10-15 minutes. Cover with waxed paper placed directly on the surface and cool to room temperature, about 30 minutes.

In a large bowl, on the medium high speed of an electric mixer, beat the butter for 3 minutes, until smooth and creamy. Gradually add the sugar, beating continuously for 3 minutes until fluffy. Add the vanilla and beat well.

Add the cooled milk mixture, and continue to beat on the medium high speed for 5 minutes, until very smooth and noticeably whiter in color. Cover and refrigerate for 15 minutes (no less and no longer—set a timer!). Use immediately.