While pasta is cooking, in an oven safe pan, melt butter over medium heat in an oven safe pan and add in flour.
Cook and stir together for one minute. Add in the garlic powder.
Pour in the milk and stir with a whisk until no more lumps remain in the pan.
Bring to a boil and turn down to simmer. Continue to cook and stir for 5-7 minutes, until the sauce thickens.
Turn off the heat and season with salt, pepper and nutmeg, stir to combine.
Add in the shredded cheese, reserving about 1/4 cup for the top. Stir the cheese into the sauce until it is melted and the sauce is smooth.
Fold the pasta into the cheese sauce until well combined. Top the macaroni and cheese with the remaining shredded cheese and place in the oven under the broiler for 3-5 minutes until the cheese is melted, bubbly and golden.
The last step of placing more cheese on top and cooking under the broiler is optional, but adds so much flavor. If you don't have an oven proof pan, you can make the macaroni and cheese and then transfer to a baking dish before topping with cheese and placing under the broiler.