Preheat oven to 350° F.
Lightly spray a shallow baking dish with vegetable oil.
Cut tomatoes in half.
Remove seeds and discard.
Scoop out a small portion of pulp and place it in a small bowl.
Set tomatoes, cut side up, in prepared baking dish.
Mix pulp together with onion powder, basil, oregano and pepper.
Stuff tomatoes with this mixture.
Top with cracker crumbs, dot with margarine and sprinkle with chopped parsley.
Bake 20 to 30 minutes, or until tomatoes are tender.
In place of ingredients listed above, mix tomato pulp with 2 tablespoons acceptable margarine, melted; 1/4 cup fresh, fine bread crumbs (1/2 slice bread); 2 cloves garlic, minced; 1 teaspoon chopped parsley; 1/8 teaspoon black pepper.
Stuff tomatoes and bake for 30 minutes, or until tomatoes are tender.