Velvety smooth cheese sauce, perfect over your favorite tortilla chips.
Melt the butter in a saucepan on medium-high heat. Whisk the cornstarch into the butter until it becomes a paste, 30 seconds to a minute. Gradually whisk in the milk until the paste smooths out, 1 to 2 minutes. Let the paste simmer until it's sauce-like in consistency, about 2 minutes.
Whisk in the Cheddar, cream cheese, taco seasoning, and hot sauce into the sauce until it's a single, smooth mix, 1 to 2 minutes more. If you want the sauce thicker, add more milk. Keep the sauce warm until it's time to use it.