Stir flour into milk.

Cook on low heat in a small saucepan until boiling, stirring constantly.

Transfer to a small bowl.

Cover with plastic wrap and let cool on the counter-top for 30 minutes.

Add the rest of the ingredients and beat with a hand-mixer until fluffy.

Store in the fridge.

*Variations* A softened 8-oz. block of Philadelphia Cream Cheese may be beaten in for a richer frosting. Hershey's Unsweetened Cocoa Powder can be added a tablespoonful at a time until desired flavor/color has been achieved. This produces a rich-tasting chocolate/peanut butter frosting.