• 2 tsp. chopped fresh rosemary, plus 1 or 2 small sprigs
Preheat grill to medium-high. Pat the pork dry, season with pepper and 1/4 teaspoon salt and brush with mustard to coat. Lightly oil the grill. Grill tenderloins for 2 to 3 minutes per side (the center-cut pork loin filet for 5 to 7 minutes per side), turning a quarter-turn at a time, until an instant-read meat thermometer inserted in the thickest part registers 145 degrees and the meat is juicy and slightly pink in the center. Transfer to a cutting board and let rest for 10 minutes.
Meanwhile, combine the peaches, wine, honey, lemon zest, rosemary and remaining 1/4 teaspoon salt in a large skillet. Cook over medium-high heat until the peaches are just tender, 5 to 7 minutes, and liquid has reduced and slightly thickened (it should lightly glaze the peaches). Transfer to a bowl.