For the stuffed and wrapped ailerons, first thaw the ailerons.
Cut the thick ribs of the savoy cabbage leaves flat. Put them into a sieve.
Bring the soup to a boil. Pour in the ailerons and poach for 10 minutes just below boiling. Hang the colander over the roasting pan and steam the aileron leaves.
Drain the savoy cabbage leaves on paper towels. Scoop the ailerons out of the soup and let cool a bit. Whisk the egg yolks and Boursin together until smooth.
Skin the meat and scoop out the bones. Pour the Boursin mixture into the ailerons. Close the meat, pressing it together carefully. Wrap each aileron in a leaf of savoy cabbage and pin with roulade skewers.
Heat the clarified butter in a frying pan. Fry the aileron packets until crispy on all sides.
Arrange the stuffed and wrapped ailerons and serve.