Bring a large pot of water to a boil. Add a teaspoon of vegetable oil to the water and pour in the dry macaroni. Cook until al dente and drain. (Note: you can cook the full 2 cups of noodles, then just stir as much of it as you like into the sauce later. Store the leftovers in a Ziploc bag in the refrigerator and use for something else later.)

Meanwhile, melt the butter in a small sauce pan over low heat. After it’s melted, whisk in the flour and continue whisking for about 1-2 minutes to dissolve and cook the rawness out of the flour. Pour in the milk and whisk slowly until it thickens. Add the cheese slices a few at a time and whisk until they melt into the sauce.

Stir the cheese sauce and noodles together, and season to taste.