1Heat the olive oil in a large pot over medium-high heat.
Add the oxtail pieces and brown them on all sides. Remove and set aside.
In the same pot, add the chopped onion, sliced carrots, and sliced celery. Cook until the vegetables are softened, about 5-7 minutes.
Add the minced garlic and cook for another minute.
Stir in the tomato paste, thyme, rosemary, and bay leaf. Cook for another 2 minutes.
Pour in the red wine and bring to a boil, scraping up any browned bits from the bottom of the pot.
Return the oxtail to the pot and add the beef broth. Bring to a boil.
Reduce the heat to low, cover, and simmer for about 3 hours, or until the oxtail is tender and the meat is falling off the bone.
Season with salt and pepper to taste.
Serve hot, garnished with fresh herbs if desired.