Sprinkle grouper fillets with salt and pepper. Dredge fillets on all sides in flour. Melt 2 tablespoons butter and olive oil in a large skillet. Add fillets to skillet; cook until browned and cooked through, about 5 minutes on each side. Remove fish from skillet.
Add lemon juice and wine to skillet, scraping browned bits from the pan. Cook 2 minutes or until slightly thickened. Remove from heat; stir in remaining 1 tablespoon butter, capers and parsley. Serve sauce over fish.