This is a great weekend meal; there’s nothing difficult about it, nothing takes more than a half-hour of attention, and with the slow cooker going, you can come and go while dinner fixes itself. If you’d rather not use a slow cooker, bring the short ribs and other ingredients to a boil in a 5-quart Dutch oven over high heat. Transfer to a 350°F oven and cook until the meat is falling off the bone, about 3 hours.
- 2 pounds bone-in beef short ribs, cut into 2-inch cubes by your butcher
- 1/2 cup balsamic vinegar
- 7 cloves garlic, 6 thinly sliced and 1 smashed
- 2 jalapenos seeded and sliced
- 2 tablespoons Dijon mustard
- grated zest of 2 lemons
- 2 teaspoons sea salt
- 3 large red onions halved
- 1 celery root peeled and diced
- 1 13.5-ounce can unsweetened coconut milk
- Preheat the broiler.
- Line a rimmed baking sheet with foil and arrange the short ribs, meat-side up, evenly on the sheet. Place the baking sheet about 4 inches under the broiler. Cook, turning the ribs occasionally, until each side is deep brown, 15 to 20 minutes total.
- Combine 2 cups of water, the vinegar, sliced garlic, jalapenos, mustard, lemon zest and 1 1/2 teaspoons of the salt in a 6-quart slow cooker. Add the ribs in an even layer. Cook on high for 4 hours. The meat should be tender when pierced with a fork.
- Preheat the oven to 450°F.
- With a slotted spoon, transfer the meat from the slow cooker to a plate. Pour the cooking liquid into a gravy strainer to skim off the fat. Do not discard the fat (you should have about 1/4 cup).
- Add the skimmed cooking liquid to a medium saucepan. Cook over high heat until glossy and thickened and reduced to about 1 cup, 18 to 20 minutes. Remove from the heat. Moisten the short ribs with about 1/4 cup of the sauce and set aside the rest to serve at the meal.
- Meanwhile, on a large rimmed baking sheet, toss the onions with the reserved fat and the remaining ½ teaspoon salt. Arrange the onions, cut- side down. Roast, without turning, until the onions are browned on the underside, about 15 minutes. Flip and roast until the onions are tender, about 5 minutes more. Tent with foil and set aside.
- Combine the celery root, coconut milk, 1 cup of water, and the smashed garlic in a 3‑quart saucepan over medium heat. Bring to a boil, reduce the heat to low, and simmer, stirring occasionally, until the celery root is very tender, 25 to 30 minutes.
- Strain the celery root, reserving the cooking liquid. Transfer the celery root and about half of the cooking liquid to a blender. Blend with enough liquid to make a smooth puree, but not a sauce, scraping down the sides of the blender bowl frequently. If you have used all of the cooking liquid and your puree is still too thick, add a little water and continue to blend until it reaches the desired consistency. Transfer to a small saucepan and keep warm.
- Serve the short ribs with the celery root puree and roasted onions on the side, along with the gravy.