Preheat the oven to 425 degrees F (220 degrees C).

Cut away excess fat from lamb chops (some fat does add flavor). Coat each chop lightly in olive oil. Season lamb chops with garlic, rosemary, salt, and pepper. Place lamb chops in a cast iron skillet.

Bake uncovered in the preheated oven until cooked through, 8 to 10 minutes. An instant-read thermometer inserted into the center should read at least 140 degrees F (60 degrees C) for medium-well doneness.

Remove from the oven and cover tightly with foil; let rest for 8 to 10 minutes. Serve with mint jelly on the side.