Cooked Salad Dressing - cooking recipe

Ingredients

1/4 c. sugar
1/4 c. flour
2 tsp. salt
2 tsp. dry mustard
1 1/2 c. milk
1/2 c. vinegar or lemon juice
4 egg yolks, slightly beaten
1 Tbsp. butter

Preparation

Mix sugar, flour, salt and mustard in saucepan.
Gradually blend in milk and vinegar.
Cook over low heat, stirring constantly until mixture thickens and boils 1 minute.
Stir at least half of hot mixture slowly into egg yolks.
Stir this mixture into remaining hot mixture in saucepan.
Bring to a boil, stirring constantly.
Boil 1 minute.
Remove from heat and stir in butter.
Cool.