Set the short ribs out onto a platter. Season all sides with kosher salt, and let them rest at room temperature for 20 minutes. After 20 minutes, sprinkle the cracked black pepper onto all sides.
Set the temperature of a two-quart slow cooker to "low". Cover with the lid.
Heat olive oil in a large skillet over medium-high heat. Add the seasoned short ribs to the pan, and brown on all sides. Let a crunchy, brown crust form, about 2-3 minutes per side, per short rib. Remove the pan from the heat, and carefully transfer the short ribs to the slow cooker. Cover with the lid.
Turn the heat on the stovetop down to medium, and allow the pan to cool (off the heat) for a few minutes.
Return the pan to the stovetop, and add the finely chopped onion, grated carrot, and celery salt. Stir to coat in the remaining oil, and cook for about 4-5 minutes until softened. Stir in the garlic, and cook for about a minute until fragrant and softened.
Stir in brown sugar, miso paste, and ancho chili powder. Cook for two minutes.
Pour in the red wine into the pan, stirring it into the other ingredients. Allow it to come to a simmer, and continue simmering for about five minutes until slightly thickened.
Stir in the beef broth, and allow it to cook with the other ingredients for about five minutes, stirring occasionally. Stir in the apple cider vinegar.
Turn off the heat from under the pan, and carefully pour the contents of the pan into the slow cooker. Add the bay leaf and thyme sprigs.
The short ribs should be covered in liquid inside the slow cooker. If a couple are barely poking out of the top, that's ok! Cover the slow cooker with a lid, and allow them to cook for eight hours.
After eight hours, the bones should cleanly slide out of the short ribs, and the meat should be tender enough to fall apart with a fork.**
Discard the bay leaf and thyme sprigs, and shred the short ribs in the slow cooker, or in a separate bowl. Serve them over creamy parmesan risotto or garlic parmesan mashed potatoes (both recipes linked in the notes!)***
To make a sauce from the remaining liquid, heat a small saucepan over medium heat. Add about 2 cups of the liquid from the slow cooker, and whisk with a cornstarch slurry**** until thickened. Pour over the short ribs, and enjoy!
Notes
*If you don't have access to rich, concentrated, flavorful beef broth from a specialty market or butcher shop, I recommend using Better than Bouillon Roasted Beef base (find it near the broths at your grocery store!). Mix two teaspoons of it with two cups of hot water to create a rich, delicious broth. I've used this a few times and will always recommend it!**See the notes in the blog post if your short ribs seem too tough after eight hours. In short, they just need to cook longer, so don't worry! Just give them another 30 minutes to an hour to become tender.***Creamy Parmesan Risotto link / Garlic Parmesan Mashed Potatoes link (both are small batch recipes for two!) ****Mix 2 tablespoons water with 2 tablespoons cornstarch. Whisk them together until they're totally combined. Whisk them into the liquids in the saucepan, and continue cooking the sauce until it thickens. Add additional slurry if needed.