Step 1

Thinly slice 1 large onion and place in a medium bowl. Trim off the surface fat from a (3-pound) beef brisket if the fat is more than 1/4-inch thick. Cut the brisket in half if needed to fit in an electric pressure cooker or Instant Pot. Season the brisket all over with 2 teaspoons of the kosher salt and 1/2 teaspoon black pepper.

Step 2

Heat 1 tablespoon vegetable oil in the pressure cooker with the Sauté function until shimmering. Add the brisket (sear in 2 batches if needed) and sear undisturbed until browned on the bottom, 5 to 6 minutes. Flip the brisket and brown on the other side, 5 to 6 minutes more. Transfer to a large plate.

Step 3

Add the onion and remaining 1/2 teaspoon salt to the pressure cooker and sauté until onions are tender, scraping brown bits from the bottom of the pot, 4 to 6 minutes.

Step 4

Stir in 1/3 cup low-sodium beef broth, 1/3 cup red wine vinegar, 1/3 cup ketchup, 1/4 cup packed light brown sugar, 1 teaspoon dried thyme, 1 teaspoon dried oregano, 1 teaspoon paprika, and 3/4 teaspoon garlic powder. Return the brisket to the pot, overlapping the pieces if needed.

Step 5

Lock the lid on and check that the valve is set to seal. Set to cook for 70 minutes under HIGH pressure. It will take 5 to 7 minutes to come up pressure.

Step 6

When the cook time is up, let the pressure naturally release, which will take 20 to 25 minutes. Carefully open the pressure cooker and transfer the brisket to a cutting board.

Step 7

Slice the brisket across the grain into 1/4-inch-thick slices. Serve the brisket with the onions and gravy. Garnish with fresh parsley, if desired.