Place a silicone trivet or metal rack into the Instant Pot.
Rinse corned beef- rinsing the corned beef helps to remove some of the extra brine from the outside. If the corned beef is not rinsed, it might end up being very salty. Place the corned beef, fat side up, onto the trivet or metal rack.
Pour in 4 cups of beef broth or water.
Sprinkle spice packet on top of corned beef.
Top corned beef with garlic and spread around on the top. You don't need to stir the garlic or spices into the broth as they will mix in during the pressure cooking time.
Close the pressure cooking lid and set the valve to the "seal" position and cook on high pressure for 90 minutes.
When the timer beeps and the pressure cooking cycle has ended, naturally release the pressure for 20 minutes and then quick release any remaining pressure.
Open the lid and remove the corned beef and set aside in a dish. Cover with foil.
Add the potatoes, carrots, and green cabbage to the remaining water/broth in the Instant Pot. ***If preferred, you can boil the carrots, potatoes, and green cabbage on the stovetop over medium-high heat instead of pressure-cooking them.
Close the pressure cooking lid and set the valve to the "seal" position and cook on manual high pressure for 2-4 minutes based on your preference. The longer the cooking time, the more cooked the vegetables will be.
When the timer beeps, quick-release the pressure and open the lid. It's time to eat! Enjoy!
Video
Notes
How do you cook corned beef and cabbage in an Instant Pot?Cooking corned beef in an Instant Pot is so easy to do! The most important thing to do is make sure that you cook it long enough. Undercooking, corned beef will result in chewy corned beef brisket. 90 minutes is the perfect amount of time to pressure-cook corned beef. Make sure that you cook the corned beef first and then add the vegetables at the end. If you cook everything at the same time, the vegetables will be way overcooked.How long does it take to cook frozen corned beef in an Instant Pot?When cooking frozen corned beef in the Instant Pot, you don't need to increase the pressure cooking time at all. 90 minutes is still the amount of time that it will need to pressure cook. The Instant Pot will take longer to get up to temperature and to pressurize if you are cooking frozen corned beef. During this extra time, the corned beef will start to thaw out.