Italian Tuna Casserole - I Ate The 80's

Ingredients

• 1 tbsp butter
• ½ cup diced green pepper
• 2 tbsp chopped onion
• 1 1 1/2 oz. package Schilling Spaghetti Sauce Mix
• 1 6 oz can tomato paste
• 2 ¼ cups water
• ½ tsp dried oregano
• ¼ tsp pepper
• 3 cups (8 oz) spiral macaroni
• 1 12 oz can tuna, drained and flaked
• 1 ½ cups shredded mozzarella