Cook the macaroni according to the package instructions in a large pot of salted boiling water until al dente. Drain and set aside.

Grate the cheddar, gruyere, and mozzarella cheeses. Set aside.

In a medium-sized saucepan, melt the butter over medium heat. Once melted, add the flour and whisk continuously to form a smooth roux. Cook for 1-2 minutes to remove the raw taste of the flour.

Gradually pour in the milk while whisking continuously to avoid lumps. Keep whisking until the mixture thickens and becomes smooth.

Add salt, pepper, and nutmeg to the sauce. Adjust the seasoning to your taste. Continue whisking until the sauce reaches a creamy consistency.

Add the grated cheddar, gruyere, and mozzarella cheese to the sauce. Stir until the cheeses are fully melted and the sauce is smooth and creamy.

Add the cooked macaroni to the cheese sauce. Stir well, ensuring that all the macaroni is coated evenly with the creamy cheese sauce.

Once everything is well combined and heated through, remove the mac and cheese from the heat.

If desired, you can garnish with additional grated cheese, herbs, or breadcrumbs for added texture.

Serve the Homeroom Mac and Cheese hot, straight from the pot. It's a comforting and indulgent dish that's sure to be a hit!