Cheese-Bacon Stuffed Tomatoes

4  medium tomatoes
12 bacon slices
1/2 cup green pepper, chopped
1/2 cup onion, chopped
1 ½  cup  shredded cheddar cheese
2 tablespoons lettuce, chopped
2 tablespoons crushed cheese crackers
4 teaspoons butter

Cut thin slice from top of each tomato; scoop out pulp and set aside. Drain tomatoes upside down on rack. Meanwhile, in a skillet. Cook bacon until almost done. Drain off fat. Add pepper and onion; sauté until soft. Remove skillet from heat and blend in cheese, lettuce and tomato pulp. Fill each shell with half of mixture. Sprinkle with cracker crumbs and dot each with 1 teaspoon butter. Place in buttered baking dish. Bake in preheated 400°C  (400°F) oven 25 to 30 minutes.