Step 1

Put salt and pepper on the brisket pieces and let it sit while you get your other ingredients together.

Step 2

In a small cup or bowl, mix together all the ingredients for the sauce.

Step 3

Place sliced onions in the inner liner of your pressure cooker or Instant Pot. Place the sliced beef on top.

Step 4

Pour over the mixed sauce.

Step 5

Cook the meat at high pressure for 35 minutes for a brisket with some chew, and at 40-45 minutes for a more tender brisket. If you intend to shred it, you can cook for 60 minutes.

Step 6

Open the pot and remove the brisket with tongs.

Step 7

Using an immersion blender, blend together the onions and all the liquid in the pot. Add mustard and ensure it is mixed well.

Step 8

Turn your Instant Pot to sauté and add the xanthum gum or corn starch and allow the sauce to thicken.

Step 9

Slice the brisket, and serve with the sauce.

Step 10

You can make this recipe in a slow cooker by following all directions as above, and cooking the brisket on low for 8-9 hours.