1 egg
1/2 c. sugar
2 tbsp. flour
3 tbsp. butter
1 tsp. prepared mustard
1 tsp. salt
4 tbsp. vinegar
1 c. cold water

Beat egg well, add dry ingredients, blend in vinegar and water. Cook in top of double boiler until thick. Remove from heat, add butter and mustard. Pour over 4 to 6 cups diced potato salad mixture. Add boiled eggs, add chopped celery and onion. If not enough dressing - Miracle Whip or sour cream may be added.