Your local supermarket will not sell tiger fish; substitute any fillets of white fish, for example sole or Bream.
100 g (4 oz) butter, plus a little for frying the fish
½ medium Onion, very finely chopped
4 plum tomatoes, skinned, seeded and diced
2 garlic cloves, finely chopped
450 g (1 lb) spring cabbage, chard, rape greens or spinach, very finely chopped
400 g (14 oz) fish fillets
2 tablespoons lemon juice
1 level dessertspoon chopped fresh parsley
1 tablespoon ground fresh nuts, for example, peanuts, almonds, walnuts, etc. (optional)
lemon wedges, to garnish
Melt half the butter in a pan and sauté the Onion and tomatoes for a few minutes until soft.
Add the garlic and cabbage, cover the pan, and cook over a low heat for about 6 minutes until tender, checking and stirring from time to time.
Meanwhile, heat a knob of butter in a pan and quickly fry the fish fillets on both sides until golden. Remove from the pan and keep warm.
Wipe out the pan, put in the remaining butter, and cook for a few moments until golden.
Stir in the lemon juice and parsley, heat through and pour over the fish.
Garnish with the nuts and lemon wedges.