Combine onion, pear, garlic, ginger, mirin, soy sauce, and hot sauce (if using) in a food processor or blender and blend until smooth. Taste sauce; add salt and/or more heat, to taste.

In an Instant Pot/electric multicooker: Arrange short rib pieces in a single layer. Pour blended sauce over, and stir to coat. Secure the lid and set the pressure release valve to Sealing. Select the Meat/Stew setting for 35 minutes at high pressure. When the timer goes off, you can perform a quick release by moving the pressure release valve to Venting, but do so with tongs or a spoon because the pressured steam release will absolutely burn your hand. Open the pot and add the carrots and daikon. Secure the lid on the pot again, and set the pressure release valve once again to Sealing. Select Cancel to reset the cooking program, then select the Manual program and set the cooking time for 3 minutes at high pressure. Perform another quick release when the time is up (moving the valve to Venting). Open the pot and use a slotted spoon to remove the meat and vegetables from the cooking liquid, then use a spoon or fat separator, if you have one, to skim as much of the fat as possible from the surface of the sauce. Taste the sauce for seasoning and adjust as needed, then spoon the sauce over the meat and vegetables. Garnish with sesame seeds and scallions.

In the oven: Heat oven to 325 degrees F. Combine short rib pieces and blended sauce in a heavy casserole dish or Dutch oven. Cover tightly with foil and a tight-fitting lid, if you have one. Bake in oven for 3 hours total, but after 2 hours, add the carrots and daikon. To check for doneness, carefully remove the lid and foil (trapped steam can burn you) and pierce the meat with the tines of a fork or point of a knife; it should yield easily. Taste a bit you pull off if you’re not sure. Use a slotted spoon to remove the meat and vegetables from the cooking liquid, then use a spoon or fat separator, if you have one, to skim as much of the fat as possible from the surface of the sauce. Taste the sauce for seasoning and adjust as needed, then spoon the sauce over the meat and vegetables. Garnish with sesame seeds and scallions.

To serve: We ate this with white rice, a quick cabbage salad (thinly sliced napa cabbage, grated carrots, and thinly sliced scallions dressed with rice vinegar, toasted sesame oil, red pepper flakes and salt to taste), and a quick cucumber salad (thinly sliced small cucumbers lightly marinated in rice vinegar, salt, a pinch of sugar, and pepper) and gochujang (Korean hot chili paste) on the side.

Do ahead: Short ribs are so good the second and third days, if you have any chance to plan ahead, you should. They keep in the fridge, buried in their braising liquid, for 4 to 5 days. They’re also much easier to de-fat; it will solidify once chilled and be easy to remove before reheating.