1. Heat about half the oil in a stock pot. Season the chicken drumsticks with salt and pepper then fry in batches, making sure the skin is nicely browned on each one. Leave to one side.
2. Heat the rest of the oil in the stockpot and fry the onion with a little salt until soft. Add the garlic and fry for another minute.
3. Pour in the tomatoes and stock then bring to the boil. Add the white wine vinegar and rosemary, then simmer for 20 minutes so it reduces down in size and thickens.
4. Season with salt and pepper then put the chicken in the sauce, cover and simmer on a low heat for 40 minutes until the chicken is cooked through. Serve with rice or pasta.