Ingredient:

• 4 hoagie buns
• 1/4 cup mayonnaise
• 2 teaspoons canola oil
• 1/2 medium onion, chopped
• 1 pound ground beef
• 3/4 teaspoon salt
• 1/2 teaspoon pepper
• 8 slices American cheese
• 2 tablespoons ketchup
• 2 tablespoons yellow mustard
• 1 medium tomato, thinly sliced
• 1-1/2 cups shredded iceberg lettuce