In the Instant Pot, combine dried macaroni,water, and salt.
Place the lid on the Instant Pot, and close bytwisting in place. Close the valve.
Set the Instant Pot to High Pressure at 4 minutes (The Instant Pot will take about 12 minutes to come pressure.).
Once the Instant Pot finishes cooking after the 4 minutes, open the valve using something to protect your hands as the steam will be hot.
Turn Instant Pot off.
After the Instant Pot has released all its pressure, untwist the lid, and pull the lid off away from you.
Stir in the milk, and butter.
Once the butter has melted, and the milk has been mixed completely, add in the cheddar, and the mozzarella by one handful a ta time. Once you have added one handful, mixed until the cheese has been completely melted. Then add another handful of cheese. Continue until all cheese has been added, and all cheese is melted in the macaroni.
Serve immediately, or you can set the Instant Pot to the “warm” setting.
I used mild cheddar cheese to make this recipe. But, you can use any type of cheese that you want to use.