Liberally salt the short ribs on all sides.

Preheat the Instant Pot by selecting Sauté and adjust to More for high heat. Heat the oil until it shimmers.

Add the short ribs in a single layer without crowding them (work in batches if necessary). Brown the ribs for three to four minutes on each side, then transfer to a plate and set aside, leaving the cooker on high heat.

Add another coat of oil if the pan is dry and heat it until shimmering.

Add the carrots, onion, and garlic.

Sprinkle with half a teaspoon of salt and stir until the onion pieces separate and the vegetables begin to soften, two to three minutes.

Stir in the tomato paste and cook for a few minutes, just until the paste begins to brown slightly.

Add the wine and stir, scraping the bottom of the pot to dissolve the browned bits. Bring the liquid to a boil and cook until the wine has reduced by about a third, two to three minutes.

Add the beef broth, thyme, and bay leaf. Add the ribs; the meat should be partially but not completely submerged in liquid.

Lock the lid into place. Select Manual (or Meat); adjust the pressure to High and the time to 40 minutes.

After cooking, naturally release the pressure for 20 minutes, then quick release any remaining pressure.

Unlock and remove the lid. Carefully transfer the ribs to a plate or baking sheet. They’ll be quite tender and will fall off the bones if you’re not gentle.

Tent lightly with aluminum foil to keep them warm while you finish the sauce.

Strain the sauce mixture through a coarse strainer into a fat separator and discard the solids.

When the fat has separated, pour the sauce back into the pot. (If you don’t have a fat separator, strain the sauce and let it cool until any fat has risen to the top. Remove as much fat as possible with a spoon or use paper towels to blot it off, then return the sauce to the pot.)

Select Sauté and adjust the heat to Normal. Bring the sauce to a simmer, stirring frequently to prevent it from scorching, until the sauce is the consistency of gravy, eight to 10 minutes.

Season with black pepper and taste. If the sauce is too acidic, add the brown sugar. Add more salt if necessary.

Return the ribs to the pot and heat them for a minute or two.

Serve and garnish, if desired, with a few additional sprigs of fresh thyme on each plate.