Sauté: • Arrange the bacon pieces in the Instant Pot and select the "Sauté" function on the "Low" setting. Cook the bacon, stirring frequently, for 6 to 8 minutes, until crisp. Remove the bacon to paper towels, leaving 1 tablespoon of drippings in the pot. • Add the chopped onion to the drippings in the pot and cook, constantly stirring, until the onion is translucent. Add the garlic and cook for an additional 1 minute. • Cancel the saute function and add the macaroni, water, butter, kosher salt, dry mustard, and black pepper to the pot. 

Pressure Cook: • Secure the lid and ensure the steam release valve is set to sealing. Choose high pressure (manual or pressure cook button) and set the timer for 3 or 4 minutes, or about half the time recommended for boiling on the package of macaroni (for al dente 7-minute macaroni and cheese, I set it for 3 minutes and 5 minutes natural release). • When the time is up, let the pressure release naturally for 5 minutes, then perform a quick release following the Instant Pot instructions.

Finish the Dish: • Stir in the evaporated milk and cheddar cheese. Add the bacon and chopped parsley and stir to blend. 

Serve: • Garnish servings with extra chopped parsley, if desired.