In an Instant Pot, combine the macaroni, 4 cups water, and salt. Secure the lid, close the valve, and cook on high pressure for 4 minutes. Manually release the steam to prevent the noodles from overcooking. A very small amount of water (1-2 tablespoons) should remain in the pot; drain any excess if needed.
Add the cream, Parmesan, and cheddar. Stir to combine until the cheese is melted. Add pepper, peas and sriracha if using. To serve, scoop into individual bowls.
