Pizza Soup

1 tablespoon vegetable oil
1/2 cup fresh sliced mushrooms
1 onion, chopped
1/4 cup chopped green bell pepper
2 - 14.5 ounce cans stewed tomatoes
8 ounces sliced pepperoni sausage
1 cup beef stock
1/2 teaspoon dried basil
1 cup shredded mozzarella cheese

Heat oil in a saucepan over medium heat. Stir-fry onions, mushrooms, and green pepper until soft but not brown.
Add tomatoes, beef stock, pepperoni and basil. Cook until heated through. Sprinkle cheese over each bowl.