Wash the meat and dab dry. Rub all around with salt and pepper and turn in the flour. Peel and chop onions and garlic. Wash sage and pluck leaves from the stalks.
Pluck rosemary needles from the branch. Chop both finely. Heat the oil in a large frying pan and fry the leg slices on both sides. Add onions, garlic and half of the herbs to the meat and fry.
Add the stock and strained tomatoes, cover and stew over medium heat for two to 2 1/2 hours. Clean, wash and finely dice the carrots and celery stalks. After 1 3/4 hours cooking time add to the meat and cook.
Remove the meat and season the vegetables with salt and pepper. Arrange the meat on top. Mix lemon peel and remaining herbs and sprinkle over the meat. Garnish as desired with lemon slices and parsley leaves.