Cheese sauceMake a white sauce, increasing the milk to 3/4 cup. Add 3/4 cup shredded cheese to the sauce. Appropriate cheeses are swiss, cheddar, american, Gruyere, etc. If using a very strong cheese, such as bleu or parmesan, decrease the amount to only 1/4 cup. Whisk until melted and smooth.
For Nacho Cheese, use american cheese and add a few pinches of chili pepper flakes.
For very smooth sauce, use a velveta-type block cheese, about a 1/2 in slice, roughly 1/4 cup. Cheddar or american can be added to cheesy it up.
Add salt and other spices and seasonings to taste.