This is a delicious sauce for gefilte fish that I always make especially for Pesach. Everyone in the family looks forward to it. It would work year-round, and would be equally good with salmon or roast beef.
1 small granny smith apple
1 small red onion
¼ cup drained prepared horseradish (without beets)
2 Tbsp vinegar
1 Tbsp sugar
½ tsp salt
¼ tsp pepper
1 cup mayonnaise
Peel and core the apple. Peel the onion. Grate the onion and apple in a food processor. Remove the grated apple and onion to a bowl.
Add the horseradish, vinegar, sugar, salt, and pepper to the bowl. Stir well. Stir in the mayonnaise and mix just until the ingredients are combined.
Cover and refrigerate for at least one hour before serving.