1/4 cup mayonnaise
2 Tbs Parmesan cheese, divided
1 Tbs Dijon mustard
1 Tbs prepared horseradish
1 Tbs lemon juice
1/2 cup dry bread crumbs, divided
4 (4 oz ea) flounder or other white fish fillets
1 Tbs butter, melted

Blend mayonnaise, 1 Tbs parmesan cheese, mustard, horseradish, and lemon juice in a small bowl, stir in 1/4 cup bread crumbs. Arrange fish on a greased baking sheet, spread crumb mixture evenly over fish. Combine remaining cheese, bread crumbs, and melted butter; sprinkle over fillets. Bake at 350 for 15-18 mins or until fish flakes easily with a fork.