Cheesy Burger Pasta Skillet

Ingredients

• 1/2 cup chopped onion
• 1/2 teaspoon garlic salt
• 1 pound ground beef
• 1 1/4 cups water
• 1/2 cup chopped tomatoes
• 1 can (15 oz) tomato sauce
• 1/2 cup chopped lettuce
• 1/4 cup ketchup
• 1 tablespoon Worcestershire sauce
• 1 tablespoon yellow mustard
• 1 cup shredded Cheddar and Monterey Jack cheese blend
• 2 cups uncooked medium pasta shells