Best Red Velvet Frosting (not cream cheese)

1 c. milk
5 T. flour
1 t. vanilla extract
2 sticks margarine or butter
1 c. granulated sugar

Combine milk and flour in a saucepan over medium heat and whisk until thick.  Remove from heat and let cool to room temperature.  Add the vanilla after cooling.  In a bowl, combine butter and sugar and cream together with mixer until light and fluffy.  Add the cooled milk mixture and mix it well with the butter/sugar combo.  It might look like it's separating, but just keep mixing.  It will get fluffier and lighter the longer you mix it, kind of the consistency of whipped cream.