How to make
Cut the kidneys in half, clean them from the skins, wash them and fill them with water, adding the peeled onion, cut into four and the celery root, cut into cubes, into the water.
Leave them for about 30 minutes.
Take the lamb kidneys out of the water, dry them, cut them into pieces and set them aside.
Place the pan on the stove along with the oil.
After it heats up, add the lamb's kidneys and start frying.
After about 15 minutes, pour the cognac, add salt and let the pan-fried kidney stew until the liquid evaporates completely.
Add the savory herb and remove the fried lamb kidneys from the heat.