Heat butter and olive oil in saucepan. Add onion, celery, green pepper and garlic; sauté until tender, about 15 minutes.
Stir in tomatoes with their liquid, sugar, tomato paste, vinegar, mustard, Worcestershire, lemon slices and bay leaf. Simmer, covered, stirring, 30 minutes, until thickened.
Discard lemon and bay leaf. Puree sauce in processor or blender. Stir in Tabasco, salt, pepper. Serve warm. Refrigerate leftover several weeks.
Shape 1 pound ground beef into 4 patties. Grill or broil 10 minutes or until desired doneness; turn once; baste with 1/4 cup barbecue sauce last 5 minutes. Serve on toasted English muffins with lettuce, tomato, red onion. Makes 4 servings.