Preheat the oven to 450ºF.

Place the pork on a work surface. Hold a long, sharp knife parallel to the work surface and cut the pork almost in half, stopping about ½ inch before cutting all the way through.

Open the pork loin like a book. Place 6 lengths of twine, 14 inches each, on a work surface about 1 inch apart. Lay the opened pork on the twine.

Season the inside of the pork generously with salt and pepper.

In a small bowl, combine the chopped chestnuts, apricots, and cranberries. Sprinkle the mixture over the pork leaving about a 1 inch border.

Lay 6 sage leaves on top of the chestnut and fruit mixture.

Starting with a long side, roll the pork into a cylinder, overlapping at the top. Tie the pieces of twine, cutting off any excess.

Mince the remaining sage leaves and mix with the olive oil, mustard, 1½ teaspoons of salt, and ¾ teaspoon of pepper. Spread the mixture over the pork loin.

Place on a foil lined, rimmed baking sheet and roast for 30-35 minutes or until an instant read thermometer inserted into the meat registers 145ºF.

Remove from the oven, cover with foil, and let sit for 15-20 minutes before serving.