Pat fish dry, and sprinkle both sides with black pepper and a pinch of salt. Sprinkle with flour.
Melt 1 tablespoon of butter, in a large nonstick skillet, over medium heat.
Add fish to the pan and cook for 5 minutes or until lightly browned.
Carefully turn fish over; cook for 4 minutes or until fish flakes easily when tested with a fork or until the desired degree of doneness.
Remove fish from pan; set aside cover with foil and keep warm while you make the pan sauce.
Add the remaining 1 tablespoon butter to the pan, cook for 1 minute or until lightly browned, swirling the pan to melt butter evenly and prevent burning.
Remove pan from heat; stir in juice.
Drizzle the juice mixture over the fish.
Sprinkle with parsley.
Serve immediately with additional lemon if desired.