Making your Cheeseburger Casserole is simple with these easy steps:

1. Preheat the Oven: Begin by preheating your oven to 350°F (175°C).

2. Cook the Beef: In a large skillet over medium heat, brown the ground beef with diced onion. Cook until well browned, stirring occasionally. Drain excess fat.

3. Combine Ingredients: In a large bowl, combine the cooked macaroni, cheddar cheese soup, milk, garlic powder, mustard, Worcestershire sauce, and season with salt and pepper. If you like, add diced pickles and tomatoes for extra flavor.

4. Mix in Beef: Stir in the cooked ground beef mixture until everything is well combined.

5. Transfer to Baking Dish: Pour the mixture into a greased 9×13-inch baking dish.

6. Add Cheese Topping: Sprinkle the shredded mozzarella cheese evenly over the top of the casserole.

7. Bake: Place the dish in the preheated oven and bake for 30-35 minutes, or until the cheese is bubbly and golden brown.

8. Cool and Serve: Once done, allow the casserole to cool for approximately five minutes before serving.

These clear instructions will guide you through the entire process without a hitch!