Beef Short Ribs with Horseradish

Ingredients

• 4 lb bone-in English-cut beef short ribs (8 to 10 pieces), about 1 1/2 lb meat once cooked
• 1 1/2 tsp fine sea salt, divided
• 1 tsp freshly ground black pepper
• 2 tbsp avocado oil
• 1 large onion, chopped
• 4 carrots, cut into 2-inch pieces
• 2 ribs celery, cut into 2-inch pieces
• 6 cloves garlic, smashed
• 2 tbsp tomato paste Label: tomatoes, and salt if any
• 2 cups beef bone broth Label: beef bones, water, vegetables, herbs, and salt, with no sugar, natural flavors, or oil
• 1 tbsp apple cider vinegar
• 6 sprigs fresh thyme
• 2 bay leaves
• 2 tbsp prepared horseradish Label: horseradish, vinegar, and salt
• 2 tsp Dijon mustard Label: mustard seed, vinegar, water, and salt
• 1/2 cup finely chopped parsley
• 1 tsp finely grated lemon zest
• a 2-inch piece fresh horseradish root, peeled and finely grated (about 2 tbsp)
• 1 tbsp extra-virgin olive oil

Instructions

1. Season the ribs: Pat the short ribs dry and season all over with 1 teaspoon of the salt and the pepper. If you have time, do this the night before and refrigerate them uncovered; salt that has time to sink in seasons the meat all the way through.
2. Brown hard: Heat the avocado oil in a large skillet over medium-high heat. Brown the ribs in batches, 3 to 4 minutes on each meaty side, until deep brown all over. Do not crowd the pan, or the meat steams instead of browning. The dark crust is where the gravy's flavor comes from. Move the ribs into the slow cooker, bone side up.
3. Cook the vegetables: Pour off all but 1 tablespoon of fat. Lower the heat to medium, add the onion, and cook for 4 minutes, until softened. Add the tomato paste and garlic and cook, stirring, for 2 minutes, until the paste darkens to brick red; caramelizing it deepens its flavor and color.
4. Deglaze: Pour in the broth and vinegar and scrape up every browned bit from the bottom of the pan. Pour it over the ribs and tuck the carrots, celery, thyme, and bay leaves around them.
5. Slow-cook: Cover the slow cooker and cook on low for 8 to 9 hours, until the meat is fork-tender and pulls easily from the bone. The ribs pass the 145°F (63°C) safe point early in the cook; it is the long hours near 200°F (93°C) that melt their collagen and make them tender.
6. Make the gremolata: Shortly before serving, stir together the parsley, lemon zest, fresh horseradish, olive oil, and a pinch of salt. Grate the horseradish last, right before mixing, since its heat fades within minutes of grating.
7. Skim and reduce: Lift the ribs and vegetables onto a platter and cover with foil. Pour the liquid through a fine sieve into a fat separator or a bowl and let it settle for 5 minutes, then pour or spoon off the fat; short ribs release a lot of it. Simmer the skimmed liquid in a saucepan over medium-high heat for 8 to 10 minutes, until reduced by about half and glossy.
8. Finish the gravy: Take the saucepan off the heat and whisk in the prepared horseradish, Dijon, and the remaining salt to taste. Adding the horseradish off the heat keeps its warmth. Spoon the gravy over the ribs and vegetables and scatter the gremolata over the top.