My Mom's Swiss Steak Recipe

Ingredients

• 2 tablespoons vegetable oil
• 2 (1/2 pound) beef sirloin tip steaks
• salt and pepper to taste
• 1 cup (1 small) chopped onion
• 1 (16 ounce) can diced tomatoes
• 2 cups sliced fresh mushrooms
• 1 stalk celery, chopped
• 0.5 cup chopped green bell pepper
• 1.5 teaspoons dried oregano
• 1 bay leaf
• 1 cup water
• 2 tablespoons cornstarch