Pat the oxtail dry with paper towels, then season on all sides with tsp Kosher salt and black pepper. Heat olive oil in a large pot over medium-high heat. When hot, add the oxtail and cook, working in batches, until browned on all sides.
To the pot, add diced sweet onion, diced carrots, and diced celery. Season with Kosher salt, then cook, stirring occasionally, until softened. Stir in chopped garlic and chopped rosemary, then cook. Stir in tomato paste, breaking it apart with a spatula.
Return the browned oxtail to the pot, along with any dripping on the plate. Stir well, then pour in red wine. Raise the temperature back to medium-high, bring the mixture to a boil, then cook until it has reduced by about half.
Pour in canned crushed tomatoes and low-sodium beef broth – just enough liquid to almost cover the oxtail – then bring the mixture back up to a boil. Add a bay leave, then reduce the heat to medium-low so it’s at a gentle simmer. Cover the pot and cook.
Transfer the oxtail pieces to a large bowl or cutting board. Using two forks or your hands, shred the meat, discarding any bones and membranes. Return the meat to the pot, then stir well. This can be kept over low heat while you make the pasta.
Transfer the oxtail pieces to a large bowl or cutting board. Using two forks or your hands, shred the meat, discarding any bones and membranes. Return the meat to the pot, then stir well. This can be kept over low heat while you make the pasta.
Add the drained pasta to the oxtail ragu, then toss to evenly coat, adding pasta water as needed to help make the sauce. Turn the heat off, then stir in grated Pecorino Romano cheese and butter. Taste and adjust seasoning.
Divide the oxtail pasta into bowls, then drizzle each with a little high-quality extra virgin olive oil. Sprinkle with additional grated cheese and a pinch of flaky sea salt. Enjoy!