Doctored from The Food Network
(ingredients for 1 lb pasta)
1 tablespoon extra-virgin olive oil
2 tablespoons unsalted butter
1 small onion, finely chopped
3 tablespoons all-purpose flour
1/2 teaspoon cayenne pepper
1 teaspoon paprika
3 cups whole milk
1 cup chicken stock or broth
3 cups shredded cheddar
Heat a medium sauce pot over medium-low heat. Add the extra-virgin olive oil and heat with the butter until it melts. Add the onions and cook for 3 to 5 minutes to sweat them out and turn the juices sweet. Raise the heat a bit, then whisk in the flour, cayenne, and paprika. Whisk together until the roux bubbles up, then cook for 1 minute more.
Whisk in the milk and stock and raise the heat a bit higher to bring the sauce to a quick boil. Once it bubbles, drop the heat back to a simmer and cook until the sauce thickens, 3 to 5 minutes.
Add the cheese to the thickened sauce and stir to melt it, a minute or so. Stir in the mustard and season the sauce with salt and pepper.
Pour over macaroni or noodles of choice!