When hot, add ground beef and cook, stirring regularly, until cooked through. You want it to keep moving so that it cooks but doesn't brown and stick to the bottom of the inner pot.
Drain the fat and return to inner pot.
Stir in onion.
Cook, stirring regularly, until onion has softened, about 2 minutes.
Remove ground beef to a plate.
Add the pasta to the inner pot and add enough water to cover the pasta by 1 inch.
Put the lid on and lock it in place.
Move the pressure release valve to SEALING.
Press MANUAL and adjust time to 4 minutes.
Turn the pressure release valve to VENTING.
Drain the pasta, and return to the inner pot.
Stir in the milk and spices.
Stir in cheese until cheese has melted.
Add cooked ground beef mixture back and toss to combine.
I usually use cavatappi pasta. I’ve found that it holds us well to pressure cooking. I’ve also used large elbow macaroni. If you use a smaller noodle, you may find that you need to adjust the cooking time.
Normally, I’m not a fan of using packaged shredded cheese in macaroni and cheese. In my stovetop mac and cheese recipe, I recommend using blocks of cheese. However, store-bought shredded cheese works well in this recipe. You can vary the cheese to change the flavor. Sharp cheddar will give you a stronger flavor; mild cheddar a milder flavor. Monterrey Jack and cheddar will give you a nice ooey gooey mac and cheese. We also like triple cheddar cheese blends in this. Sometimes I even thrown in some shredded parmesan cheese for a little more bite.