Preheat the oven to 180 degrees. Cut the duck breast diagonally several times on the breast side, season with salt and pepper and sear it on this side, then turn and sear on all sides. Fry the breasts in a greased dish in the oven for about 10 minutes on the inside slightly pink or 15 minutes. After taking it out, let it rest a little, then cut it open.
Sear the quartered apples in the pan, deglaze with calvados, add some cream and season to taste. Serve with a fine potato gratin.