Sprinkle the fish with lemon juice, salt and pepper and allow to stand for 5 - 10 minutes.
Drain well and coat with the flour.
Melt half of the butter in a large frying pan or two if necessary, and heat to moderately hot.
Fry the fish on one side until golden brown.
Lift out and add more butter before turning over and cooking on the other side until done to taste.
Transfer the fish to a warm serving platter, pour over the butter and sprinkle the fish very lightly with vegetable seasoning and chopped parsley or spring onion.