2. Peel onions and carrots, wash them and cut them into small pieces; Wash celery and cut into small pieces; Mix well and put in a baking tray.
3. Wash the beef bones, put them in, move them into a preheated oven, and bake them at 250℃ until they are slightly browned.
4. Pour the water into the pot, add thyme and rosemary, bring to a boil with high fire, simmer for about 6 hours, and finally filter out the soup.