Switch on the Instant Pot to the saute setting on high. When the instant pot is hot, pour about 2 tbsp of oil. When the oil is hot, place about 3 - 4 short ribs in the instant pot to caramelize or to sear. Place the caramelized short ribs on a plate.
For the next step, you will only need about 1 tbsp of oil in the instant pot. Discard the excess oil if there's more than 1 tbsp of it in the instant pot at this point.
Place the thickly sliced onion in the pot, and add the boubon. De-glaze the bottom of the instant pot to make sure that all of the caramelized bits on the bottom are mixed with the bourbon (de-glazing is an important step, so don't skip it). Add the paprika, cayenne pepper, sugar and balsamic vinegar.
Place the short ribs back in the instant pot, and add the garlic, thyme and a pinch of salt (how much salt to add at this point depends on how well you seasoned the short ribs earlier - be careful not to over-salt, since you can always add more salt at the end if needed).
Pour the stock over the short ribs. Close the instant pot. Choose the manual high pressure function and set it to high. Cook the short ribs for 45 minutes, followed by a 10 - 15 minute natural release.
Gently remove the short ribs on to a plate, and turn the saute function back on for the liquid/broth in the instant pot.
Dissolve the cornstarch in the water and add it to the liquid/broth in the instant pot. Mix it in and bring it to a simmer until the liquid has thickened. Taste and season the liquid with more salt or balsamic vinegar, if needed. Transfer the short ribs back into the instant pot and switch off the saute function.