1 c. mayonnaise
1/3 c. sour cream
1/4 c. prepared mustard
1/3 c. chili sauce
1/4 c. minced onion
1 tbsp. horseradish
1/8 tsp. pepper

A day ahead of time, mix ingredients together. Cover and chill overnight. Remix before serving. Can be stored in refrigerator for one month. Great on sandwiches too.