Add the uncooked macaroni, water and salt to the Instant Pot. Attach the lid and ensure that the valve is in the "sealing" position. Set the timer for 4 minutes. When the timer finishes, release the pressure manually by switching the valve to the "venting" position. Be careful, the valve with steam and may splatter.
Next, add the butter, cheese, milk, garlic powder and nutmeg. Switch the Instant Pot to the Saute function and stir until the cheese is fully melted. Season with additional salt and pepper, if desired.
Serve immediately.
Notes
SUBSTITUTIONS
Macaroni: Elbow macaroni is standard, but another type of short pasta like shells or cavatappi works great too.
Cheese: The combination of cheeses in this recipe results in the creamiest, cheesiest texture and flavor. You can substitute one of the cheeses with another one of your favorite cheeses.
STORAGE
Store any leftover mac and cheese in an airtight container in the fridge for up to two days.