Season roast on all side with salt and pepper. Place in large roasting pan with rack; allow to stand at room temperature for 1 hour.
Preheat oven to 400 degrees.
Place large ball of foil in center of roast; adjust roast to form circle. Place apples around meat. Roast 1 hour, basting with pan juices every 15 minutes. Reduce oven temperature to 350 degrees; roast until instant read thermometer inserted into center of meat, away from bone, registers 140 degrees for medium, 15-30 minutes more. Transfer roast to carving board, tent with foil and let rest 15-20 minutes.
Transfer apples to platter.
Pour pan drippings into a bowl, skim off fat and reserve juices. Place roasting pan over medium heat; melt 1 tbsp butter. Add 1/2 cup finely diced shallots and 3 thyme sprigs; cook 3 minutes. Add 1/2 cup Calvados; stir to deglaze pan. Stir in reserved juices; chicken broth and veal demi-glace. Simmer 3-5 minutes. Whisk in cream; season with salt and pepper. Strain sauce into a sauceboat.
Carve roast between bones; arrange alongside apples on platter. Pour some of sauce over meat; pass remaining sauce at table.