Peel the shallots. Clean, wash and halve the mushrooms. Wash the leg, pat dry and rub with salt and pepper.
Heat the clarified butter in the roaster, fry the leg brown all over, then remove. Fry the shallots and mushrooms in the frying fat until golden brown, dust over the flour and sweat. Add water, wine and cream, bring to the boil and stir in the chicken broth, season to taste.
Put the leg back in the roaster and cover it in the preheated oven at 175 degrees air circulation for approx. 1 ¾ hours. Wash fresh thyme, pluck the leaves and sprinkle over the leg about 30 minutes before the end of cooking. Season the sauce again to taste.
Clean, wash and core the tomato, finely dice the pulp and sprinkle over it before serving.