Step 1

Put the onion, thyme, garlic, pickling spice, brisket and 6 cups water into an Instant Pot®. Follow the manufacturer's guide for locking the lid and preparing to cook.

Step 2

Seal and cook on high pressure for 85 minutes. Follow the manufacturer's guide for quick release, then remove the meat and set aside. Strain the liquid through a fine mesh strainer into a bowl and return 2 cups back to the Instant Pot® along with the butter.

Step 3

Add the rutabaga, leeks, carrots and cabbage to the Instant Pot®. Seal and cook on high pressure for 4 minutes. Quick release the steam. Thinly slice the brisket across the grain and transfer to a serving platter. Arrange the vegetables around the meat, sprinkle with the parsley and serve with the sour cream, horseradish and mustard on the side.