Wash the meat, pat dry and cut a pocket on the side. Salt and pepper the meat inside and out. Briefly blanch the spinach, rinse in cold water and drain. Finely dice the cheese. Spread 4-5 spinach leaves on a slice of ham. Spread the cheese cubes on top and sprinkle with coriander. Fold the ham slice up and slide it into the chicken breast pocket. Close with a wooden stick. Turn the meat first in the beaten egg, then in the ground hazelnuts. Press the breading on well and fry in the clarified butter!