Heat the grapeseed oil in a large Dutch oven or heavy-bottomed pot over medium-high heat. Sear the short ribs until brown on all sides, about 3 minutes per side. Reserve on a sheet tray.
Add the Asian pear, lemongrass, ginger and scallions to the Dutch oven and cook for a few minutes. Add the gochujang and tomato paste and cook another minute or two to caramelize. Add the red wine, beef stock, soy sauce, sesame oil, orange zest and juice, fish sauce, brown sugar, sesame seeds and 2 cups water and bring to a simmer. Add the short ribs back, nestling them in so they are covered with liquid. Braise in the oven for 40 minutes.
Lower the oven temperature to 250 degrees F and continue to cook until the short ribs are fork-tender, another 2 hours and 15 minutes to 2 hours and 45 minutes.
Transfer the short ribs to a sheet tray and cover with foil to rest. Strain the cooking liquid, return to the Dutch oven and reduce over medium-high heat until slightly thickened, 5 to 8 minutes. Serve the short ribs over the Sweet Potato Grits, with watercress and the sauce.
Sweet Potato Grits:
Preheat the oven to 375 degrees F.
For the sweet potatoes: Prick the sweet potatoes with a fork, wrap in aluminum foil and cook until they feel soft all the way through when you gently squeeze them, about 40 minutes. Allow the sweet potatoes to cool slightly, then scoop out the flesh and mash lightly with a fork. Set aside.
For the grits: Place 4 cups of water and 1 teaspoon of the salt in a medium heavy-bottomed saucepot and bring to a boil over high heat. Whisk in the grits. Cook, stirring, until the mixture comes back up to a boil, then reduce the heat to the lowest setting, place a lid on top and let simmer for 15 minutes.
Remove the lid and give the grits a good stir to help them finish absorbing the water. Add the sweet potatoes and stir until well mixed. Fold in the butter and nutmeg. Stir again until smooth. Add the remaining salt. Serve hot.