Sauté' onion and garlic in butter in a saucepan until tender. Stir in tomatoes and remaining ingredients; bring to a boil.
Reduce heat, and simmer, uncovered, 30 minutes; stir occasionally. Remove and discard bay leaf and lemon slices. Process mixture through a food mill or in a food processor, if desired. Use sauce for basting, or serve with chicken.
Yields: 3 cups