Cook 8 ounces elbow macaroni per the directions on the back of the box in a large stock pot or Dutch oven. Drain well and add back to the pot.
Add 1 1/4 cup whole milk, 1 1/2 Tablespoons powdered milk, 3/4 teaspoon cornstarch, 1/2 teaspoon dry ground mustard, and 12 ounces Velveeta, cut into small cubes over medium-low heat.
Stir constantly until the Velveeta is melted. Do not let this come to a simmer.
Take off the heat and stir in 1 cup shredded sharp cheddar cheese. Taste and add salt if needed.
This does thicken as it cools so if you like it thicker, just give it a few minutes to cool and stir occasionally.
Notes
Please refer to my FAQ’s (Frequently Asked Questions) and ingredient list above for other substitutions or for the answers to the most common questions.