1 egg
2 tbsp. flour
1 tbsp. mustard
1 tbsp. vinegar
1 can milk
2 tsp. sugar
1/3 c. mayonnaise (save for last)
Pinch of salt
1/4 lb. bacon, fried crisp, save fat

Cook until thick, stirring all the time. Add bacon and grease to mixture, mix well. Add mayonnaise and pour over hot, cooked, cubed potatoes.