Ermine Frosting

This is the traditional frosting for red velvet cake, before cream cheese frosting was a thing.

===== Ingredients =====
-1c whole milk
-1c granulated sugar
-4.5tbsp AP flour
-1/4tsp salt
-2 sticks unsalted butter
-1tsp vanilla

===== Instructions =====
1. Combine milk, sugar, flour and salt in a medium saucepan. Bring to a boil over medium heat, whisking constantly.
2. Allow to boil for 15-30 seconds, then pour through a fine mesh sieve into a bool and cool to room temp.
3. Stir in vanilla, cut in room-temp butter. Whisk on stand mixer for 5-7 minutes until frosting is fluffy. Keep your mixing bowl cold to make this process easier.