This recipe is based on one posted in Ozlem's Turkish Table. Sea bass is a favorite along the Aegean coast, but you could substitute any mild firm fish. Not only is this dish delicious, it is healthy and a simple one-dish meal.
Boil the potatoes for 10 minutes, then drain the water and leave to cool. Once it is cool enough to handle, cut potatoes in half and slice thinly.
While the potatoes are boiling, heat 2 tbsp olive oil in a large, heavy pan. Stir in the chopped onions and cook until soft, for 3 -4 minutes. Add the chopped garlic and tomatoes and cook over medium low heat for 3 minutes. Pour in the water and lemon juice. Season with salt and freshly ground black pepper. Cook gently for another 2 minutes on low and heat and leave to cool.
Grease a baking dish with the remaining 2 tablespoons olive oil and place the fish fillets and potato slices in the dish, coat them with the olive oil. Season with salt and freshly ground black pepper.
Spread the tomato and onion mixture over the fish fillets and place the potato slices alongside the fish. Cover the baking dish with aluminum foil and bake in the oven for about 20 - 25 minutes.
Once cooked, take the foil off and sprinkle chopped parsley and red pepper flakes over the fish. Serve immediately with wedges of lemon by the side.