1/3 cup brown sugar
¼ cup water
¼ cup vinegar
¼ cup ketchup
1 tablespoon soy sauce
1 (2-inch) piece fresh ginger, peeled and minced
1 slab St. Louis-style ribs, membrane removed
Kosher salt
Freshly ground black pepper
1 tablespoon cornstarch combined with 1 tablespoon cold water
Place the trivet in the Instant Pot.
In a small bowl, combine the brown sugar, water, vinegar, ketchup, soy sauce, and ginger and stir to mix well.
Put the ribs in a large bowl and pour the sauce mixture over them. Toss to coat. Place the ribs on top of the trivet in the Instant Pot and pour any remaining sauce over the top.
Close the lid and turn the valve to the sealing position. Select high pressure and set the timer for 30 minutes.
When the cooking time is up, let the pressure release naturally for about 15 minutes and then quick release any remaining pressure.
Remove the ribs from the pot, leaving the cooking liquid in the pot.
Preheat the broiler or grill.
Turn the pot to sauté and bring the liquid to a boil. Stir in the cornstarch-and-water mixture and cook, stirring, until the sauce thickens, 2 to 3 minutes.
Arrange the ribs on a foil-lined, rimmed baking sheet if broiling. Whether grilling or broiling, brush the ribs all over with the sauce. Grill or broil for 6 to 8 minutes, until the sauce is bubbling and thick. Serve immediately.