1 1/4 c  Milk
1/4 c  Corn starch
2/3 c  Sugar
1 c  Butter or substitute

Flavour (original recipe used 1 tablespoon instant coffee, can
substitute 1 teaspoon vanilla essence etc.)

Mix 1/3 cup milk with cornstarch in bowl. Boil rest of milk with
sugar in saucepan. If the flavour is something that needs dissolving
(eg the instant coffee), stir it into the milk. Stir milk mixture
into corn starch mixture. Return to saucepan and boil mixture while
stirring until thick and smooth.

Take off heat and allow to cool, stirring often. Add flavour if not
already added. Beat butter in large bowl until smooth. Add
milk-cornstarch mixture and beat well. Makes enough to fill and top
a 9 inch cake.