2 c. mayonnaise
3 tbsp. onion
2 tsp. lemon juice
3 tbsp. finely chopped dill pickle
2 tbsp. finely chopped parsley
2 tbsp. minced, drained capers
1 tsp. Dijon mustard
Salt and pepper

Whip mayonnaise lightly and add the remaining ingredients. Refrigerate for 1 or 2 hours. Add 1/4 cup plain mashed potatoes for a sauce that is less rich and oily.