Made with vinegar, egg, and butter.
From the box of L.R. from Winston-Salem, North Carolina.
Potato Salad Dressing
1 beaten egg
1/2 cup sugar
1 Tbsp. flour
1/2 cup water
1/2 cup vinegar
2 Tbsp. butter
1/2 tsp. salt
1/4 tsp. pepper
Combine in the order given, stirring after each addition. Boil until thick. Cool before adding to the salad.