Ingredients
2 Tbsp flour
1/4 tsp salt
1 egg yolk
1/3 cup white vinegar
1 Tbsp dry mustard
1 cup sugar
1 cup milk
1 Tbsp butter
Preparation
Mix first 6 ingredients in a medium saucepan. Slowly stir in the milk. Cook in double boiler or stir constantly over medium heat until thick. Remove from heat and stir in butter.
