Sear the tenderloins on all sides, about 5–6 minutes total, then remove them. Sauté the apples briefly in butter, add the cider, stock, mustard, and honey, then return the pork to the pan.

Roast at 375°F for about 15–20 minutes, depending on thickness, until the center reaches 140–145°F. Rest the pork for 8–10 minutes before slicing.

While it rests, reduce the cider-mustard sauce on the stovetop until glossy.