12 - ounces frozen fully-cooked beef meatballs (about 23 meatballs)
1 - teaspoon vegetable oil
3/4 - cup thin onion wedges
3/4 - cup thin green bell pepper strips
1 - jar (14 ounces) prepared spaghetti sauce
4 - hoagie rolls, split
Shredded mozzarella cheese (optional)

• Heat oil in large nonstick skillet over medium heat until hot. 
• Add onion and bell pepper; cook and stir 5 minutes or until tender.
  
• Add meatballs and sauce; bring to a boil. Reduce heat; simmer 6 to 8 minutes or until meatballs are heated through, stirring occasionally. 
• Serve in rolls. 
• Sprinkle with cheese.