1 pound elbow macaroni
4 cups chicken broth
or vegetable broth, low sodium
3 tablespoons unsalted butter
12 ounces sharp Cheddar cheese
shredded, 3 cups tightly packed
1/2 cup Parmesan cheese
shredded, about 2 ounces
1/2 cup sour cream
1 1/2 teaspoons yellow mustard
1/8 teaspoon cayenne pepper
Combine the macaroni, broth, and butter in the Instant Pot.
Secure the lid and set the Steam Release to Sealing. Select the Manual setting and set the cooking time for 6 minutes at high pressure. Perform a quick release by moving the Steam Release to Venting.
Open the pot and stir in the cheeses, sour cream, mustard, and cayenne pepper. Let sit for 5 minutes to thicken, then stir again and serve.
Optional:
If you like, finish the macaroni and cheese under the broiler for a crispy topping.
Transfer to a 3-quart flameproof baking dish, sprinkle evenly with 1 cup panko bread crumbs, and then broil for just a few minutes, until the bread crumbs are golden brown.