Fish is cleaned head and entrails and wash. Clean then the skin and bones and cut into cubes (5-6 per portion). Add salt, add some flour and fry lightly in a hot vegetable oil. In the same fat stew until soft chopped onion. Add red pepper and tomato paste. Stir and pour a little water or fish broth. Add sliced ​​julienne mushrooms, add salt and sauté on low heat. Finally, add the wine and spices. To the finished sauce add the fish and the butter. Serve each portion is added a slice of lemon.