Combine trout, onion, capers, lemon peel, pepper and salt in medium bowl. Stir in egg, cream and 1/2 cup bread crumbs to blend. Form mixture into 8 (1/2-inch thick) cakes. Place remaining bread crumbs in shallow dish then roll cakes in bread crumbs, coating completely. Heat 2 tablespoons oil in large skillet over medium heat. Working in batches cook fish cakes until golden brown about 3 minutes per side. Add more oil, as necessary, then serve with horseradish cream.
In a medium serving bowl, combine sour cream, horseradish, paprika, chives, garlic, salt and pepper until blended.