Horseradish cream sauce:
1 cup sour cream
1/4 to 1/2 cup grated fresh horseradish (depends how strong you like it!)
1 Tbsp Dijon mustard
1 tsp white wine vinegar
1/2 tsp kosher salt
1/4 tsp freshly ground black pepper
Mix all ingredients together with a whisk. Refrigerate a few hours before serving. May be made up at 2 days ahead and kept tightly covered in fridge..