Step 1

In a saucepan over medium heat, melt the butter.

Step 2

Add the flour and whisk constantly for 1-2 minutes (or until the mixture turns light brown).

Step 3

Remove from heat and gradually pour in the warm milk, whisking constantly.

Step 4

Return the pan to the heat, whisk another 3-5 minutes or until thickened.

Step 5

Add the salt, garlic powder, ground mustard, and cayenne pepper and stir to combine. Remove from heat.

Step 6

Add the cheeses, stirring to melt.

Step 7

Pour the sauce over the top of the cooked elbow macaroni. Stir to combine.

Step 8

Season with salt and pepper, and top with chopped parsley.