3/4 c  Granulated sugar
1/4 ts Salt
1/4 c  Flour
1 c  Cold butter
3/4 c  Milk
1 ts Vanilla

Place sugar, flour and salt in a saucepan and mix thoroughly. Stir in milk.
Cook over medium heat, stirring constantly until very thick. Remove from
heat and pour into a mixing bowl. Cool to room temp. Add half the butter —
cut into pieces– and beat at medium speed until smooth. Add rest of
butter, beat well until smooth. Add vanilla. Chill for a few minutes before
using. Cake must be refrigerated until serving.