Mix flour, salt, mustard, sugar, pepper and sage. Rub over surface of meat. Set meat aside, fat side up, in a roasting pan. Roast at 325°F for 1 ½ hours.
For topping, mix applesauce with brown sugar, cinnamon, mace and salt. Spread on top of meat. Roast about 15-30 minutes longer, or until temperature reaches 145°F to 150°. Let rest for 5 minutes before serving.
Heat up the remaining topping sauce and serve with the roast.