Ingredients
1 tsp. mustard
1 tsp. salt
1 tbsp. cornstarch
3 tbsp. sugar
1 egg, slightly beaten
1 cup milk
1/2 cup vinegar
2 tbsp. butter

Directions
Mix the dry ingredients together then add the egg and milk. Cook in a double boiler until the mixture is thick and smooth, stirring constantly. Add butter and vinegar slowly and cook until the consistency is right. If the mixture gets too thick, thin with rich milk.

Refrigerate before using.