Step 1

Place a trivet or foil collar in the bottom of a 6-quart or larger electric pressure cooker or Instant Pot.

Step 2

In a small bowl, combine salt, pepper, garlic powder, and paprika. Rub mixture over brisket and place fat side up on the trivet in the pressure cooker.

Step 3

In a medium bowl, combine brown sugar, vinegar, 1 cup water, the ketchup, and liquid smoke, if desired; pour over brisket. Lay onion slices on top of meat.

Step 4

Securely lock lid; set pressure cooker to cook 50 to 55 minutes. Perform a natural release. Be careful when opening the top as the steam will be hot. Place brisket on a cutting board to rest for 10 minutes.

Step 5

In a small bowl, whisk cornstarch and remaining 3 tablespoons water. Set on simmer or heat setting. Stir mixture into pressure cooker and simmer 8 to 10 minutes or until thickened. Slice brisket across the grain and serve sauce over brisket.