Put the tomatoes through a sieve or food mill.
Heat four tablespoons of the oil in a heavy saucepan.
Cook the onion and garlic until very lightly browned.
Add the tomatoes, salt, pepper, and sugar and cook over moderate heat until thick, about 30 minutes. Preheat the oven to 425.
Melt the butter and remaining oil in a large, heavy skillet.
Saute the Sea Bass until just done.
Add the Cognac and Ouzo, heat and flame the Sea Bass.
Place the Sea Bass in a casserole.
Cover with the tomato sauce, then with feta cheese.
Sprinkle with parsley and bake until well heated, about 10 minutes.
Serve over pasta.