In a saucepan or large frying pan, pour 1 tbsp of olive oil and fry the oxtail for 3-4 minutes on all sides, turning the pieces over. Then take the tail out of the pan and put it aside.
Add the frying oil to the pan and start frying the vegetables on low heat. Stir. After 5 minutes, transfer the fried oxtail to the pan.
Add beef broth, as well as salt and spices to the pan. You can add fresh sprigs of rosemary, thyme and bay leaf. Stir and cook covered for 2 1/2 hours. Check after 1.5 hours, if the liquid boils away during the process, add more broth or water.
After 3 hours, the meat will become very soft. You can serve the oxtail in whole pieces along with the sauce, or you can separate the meat from the bones and use the pulled beef for cooking other dishes.