Rich Filling

This was made to fill the Boston Cream Pie but could be used as filling for cream puffs or as a pudding dessert.

1/3 cup sugar
2 Tbsp cornstarch
1 1/2 cups milk
2 egg yolks, slightly beaten
1 Tbsp butter or margarine
1 tsp vanilla

Stir together sugar and cornstarch in medium saucepan; gradually add milk and egg yolks, stirring until blended. Cook over medium heat, stirring constantly, until mixture comes to a boil. Boil 1 minute, stirring constantly. Remove from heat; stir in butter and vanilla. Cover; refrigerate several hours or until cold.