One-pot mac and cheeseburger

Instructions

1. Coat a large skillet with cooking spray and heat over medium-high. Add 1 cup onion and beef; cook until the beef is browned, stirring frequently to crumble, about 5 minutes. Stir in 2 cups water, salt, garlic powder, pasta, and tomato sauce; bring to a boil. Reduce the heat to medium-low and cook, uncovered, until the pasta is tender, 10 to 12 minutes, stirring occasionally.
2. Reduce the heat to low. Stir in the milk and mustard. Gradually add the cheese, stirring until it melts. Remove the pan from the heat; stir in ½ cup tomatoes and ¼ cup pickles. Top the pasta mixture with the lettuce, remaining ½ cup tomatoes, and remaining ¼ cup each onion and pickles.
3. Serving size: about 1 cup