Instant Pot Corned Beef & Cabbage is made with the help of your electric pressure cooker and finished off under the broiler with a brown sugar-mustard glaze, giving it a perfectly crispy exterior.
Place corned beef brisket, spice packet, garlic, beer and 2 cups of water in the instant pot.
Set timer for 90 minutes on high. (It will take about 15 minutes for the pressure to build, then the timer will start) Once the time expires, allow for 15 minute natural pressure release before releasing remaining pressure and removing the lid from the instant pot.
While the pressure is natural releasing, prepare the glaze. Melt butter in small saucepan -- add water and brown sugar. Heat over medium-high heat and let thicken for about 5 minutes. Whisk in mustard and reduce heat to low, simmer 2-3 minutes. Set aside. Preheat the broiler on LOW.
Leaving the liquids in the instant pot, remove corned beef to a cookie tray. Brush some of the glaze on top of corned beef and broil on LOW, 6-inches from the element for 15 minutes adding glaze every 5 minutes. Always keep an eye on the broiler to avoid burning.
Put cabbage, potatoes and carrots in the instant pot and cook them on high for 3 minutes then do a quick release.