Add the flour, mustard, cayenne and paprika and whisk together until fully combined, cook for an additional 15 seconds.
Add in the salt and pepper and cook for an additional 5 minutes.
Remove 1 cup of the milk mixture and let cool for a 3-5 minutes in the refrigerator in a larger glass measuring cup or bowl.
Bake for 30 minutes, uncovered.
* I use blocks of cheese for my mac and cheese because shredded cheese is coated in a powder that prevents the cheese from sticking to each other. This also results in cheese that may not melt as fully and result in as creamy of a texture as we'd like.
** Removing the cup of milk, cooling, then adding in the egg allows for us to temper the egg which prevents it from immediately scrambling in the hot milk mixture.