The dried-fruit and chestnut stuffing lends flavor as well as visual appeal to the pork loin. Once rolled, add another layer of flavor to the pork with coriander seeds and peppercorns.
Preheat oven to 450 degrees. Place pork on a work surface. Hold a sharp knife parallel to work surface, and cut the pork almost in half, stopping 1 inch short of cutting through; open like a book.
On work surface, arrange six 14-inch lengths of kitchen twine, 1 inch apart. Place pork, opened up, across twine. Sprinkle with chestnuts and dried fruit, leaving a 1-inch border all around; season stuffing with salt.
Fold one long side over the other, overlapping slightly to form a cylinder; tie with twine. Rub with oil; sprinkle with cracked pepper and coriander, pressing to adhere. Season with salt. (To store, refrigerate, up to 1 day.)
Place pork in a roasting pan; roast until an instant-read thermometer inserted in meat (not stuffing) registers 145 degrees, 35 to 40 minutes. Transfer to a cutting board (reserve pan); cover loosely with aluminum foil, and let rest (temperature will continue to rise).
Place pan across two burners. Add wine; simmer, stirring constantly, until syrupy, 4 to 5 minutes. Add Dijon and broth; cook, stirring occasionally, until reduced by half, 6 to 8 minutes. Remove from heat; whisk in butter. Slice pork, and serve with wine sauce.