Fresh basil leaves (or parsley) for garnish Shell and devein shrimp. Wash and drain, then sprinkle lightly with lemon juice. Heat the oil or butter in a frying pan and cook the onion until soft. Add the tomato sauce, chopped tomatoes, herbs, garlic, and salt and pepper to taste. Simmer for 25 minutes, then remove from the heat and strain. Butter large scallop or other shells, or individual ovenproof dishes, and spoon a little sauce into each. Fill with the shrimp and spoon the sauce over, then crumble the feta over the top. Set into a baking pan and bake for 15 or 20 minutes in a moderate oven (350 F), or until the shrimp is cooked and the cheese melted. Garnish with fresh basil or parsley and serve hot.