1 red onion -- sliced
1 green pepper -- cut thin strips
4 medium zucchini -- sliced unpeeled
1 can diced tomatoes - (16 oz) -- undrained
1 teaspoon salt
1/2 teaspoon freshly-ground black pepper
1/2 teaspoon basil
1 tablespoon margarine
1/4 cup grated Parmesan cheese

Combine all ingredients, except margarine and cheese, in a slow cooker. Set temperature on LOW and heat for 3 hours. Dot casserole with margarine and sprinkle with cheese. Cook 1 1/2 hours more on LOW setting.

This recipe yields 6 servings.