Start by cutting the hat apples (keep) and empty it leaving approximately 7mm edges. Cut the flesh removed apples in small dice (making sure to remove the seeds obviously) and keep in a bowl.
Shell the walnuts (if it is not already), put it in a pan with sugar and high heat so it caramelize. Add the apples, almonds and cinnamon and reduce heat to low. Leave about 8min so that stewed apples. Add the Calvados and flambé.
Stuff the apples with the previous preparation and replace the cap. Place them in a dish and pour a background of water. Bake 25 to 30 minutes at 180 ° C.