Ultimate Creamy Baked Mac and Cheese Delight

1. Start by preheating your oven to 350°F and greasing a 9×13-inch baking dish.

2. Cook the pasta according to the package instructions until al dente. Once done, drain the pasta and set it aside.

3. In a large saucepan, melt the butter over medium heat. Stir in the flour to create a roux, and cook for 1-2 minutes, stirring constantly.

4. Gradually whisk in the milk to avoid lumps. Cook and stir until the mixture thickens. Then, stir in the Dijon mustard (if using), salt, black pepper, and nutmeg.

5. Reduce the heat to low and gradually add the shredded cheddar, mozzarella, and Parmesan cheeses, stirring until the cheese is melted and the sauce is smooth.