Boil the noodles to al dente according to the directions on the package.
8 oz. macaroni noodles
While you're boiling the noodles, combine everything except the butter in a medium-sized bowl and set aside.
6 oz. evaporated milk, 1 large egg, 1 tsp Dijon mustard, ⅛ tsp ground nutmeg, 1 tsp dried basil, 1 tsp kosher salt, 2 cups shredded cheese, freshly ground black pepper
Melt the butter in a microwave safe bowl and set aside.
4 tbsp unsalted butter
Once the noodles are done, drain and return them to the pot (turn off the heat), add the butter, and stir to coat the noodles.
Add the egg mixture to the noodles and turn the heat back up to low. Cook, stirring, for 2-3 minutes, or until the mixture thickens and the cheese is melted. Add in the Velveeta (optional) if using.
½ cup cubed Velveeta
Serve immediately (it will thicken and dry out if you wait too long).