Pour tomatoes into mixing bowl. Squeeze into small pieces. Heat 4 tablespoons oil in heavy saucepan. Lightly saute onion and garlic. Add tomatoes, sugar, salt and pepper. Cook, uncovered, over medium heat until sauce is thickened. Heat butter and 2 tablespoons oil in large, heavy skillet. Saute shrimp over medium-high heat until pink. Add ouzo and cognac. Flame shrimp. Place in casserole or individual ramekins. Cover with the tomato sauce. Sprinkle with crumbled feta and parsley. (This much of preparation can be done ahead of time.) Bake in 220ºC oven 10 minutes or until well-heated and feta has melted. Serve with crusty bread and a salad. Freezes well. Defrost when ready to use. Bake, covered, at 200ºC 10-15 minutes.