For each sandwich used 3 slices. Spread one slice with butter, cover with sausage. The second is coated on one side with butter, and the other with mustard and mayonnaise. put it feta cheese and sausage and cover with the other of which is coated only on one side with butter. Pressed well three slices. Cut diagonally, pinning him with toothpicks dipped in a mixture of beaten eggs, milk and salt and fry.