Press saute mode on the Instant Pot, add oil and wait 3 minutes.
Once the oil is hot, add the impossible meat or ground beef and saute, during cooking, with the help of a wooden spoon, break it into small pieces. Cook the meat long enough for it to be fully brown.
Add onion and bell pepper and cook for another 5 minutes until the onion is softened.
Add the rest of the ingredients except 1/2 cup of cheddar cheese and green onions. Give it a good stir.
Close the lid, and place the valve on sealing mode. Select high pressure and cook for 5 minutes. (Keep in mind that it will take about 20 minutes for the pressure to rise and start cooking)
Once cooked, release the pressure immediately, open the lid, and stir.
Serve in a hot bowl, add more cheese and green onion.
Notes
Substitutions
Here are a few substitutions for you in case you're out of a particular ingredient or follow a certain diet...
Impossible meat - For instant pot vegetarian mac, you can use impossible meat or another plant-based meat.
Different noodles - If you don't have macaroni pasta or cavatappi noodles, you can use bow-tie, rotini noodles, or penne noodles.
Ground turkey - If you're our of ground beef or rather use another type of meat, you can use ground turkey instead.
Black beans - Kidney beans and/or black beans work great in this recipe so feel free to use your favorite or add half and half.