Pat the rack dry, season generously with salt and pepper. Heat olive oil in a large ovenproof skillet over medium-high. Sear the rack fat-side down until deeply browned, about 3 minutes, then turn and sear the other side for 2 minutes. Remove from heat and let cool 5 minutes.

Brush the rack all over with the Dijon mustard.

In a small bowl, combine garlic, rosemary, panko, Parmesan, and a drizzle of olive oil. Press the mixture firmly onto the mustard-coated rack, covering the fat cap and sides.

Preheat oven to 400°F (200°C). If your skillet is not ovenproof, transfer the rack to a foil-lined baking sheet. Roast for 15-18 minutes until a thermometer inserted in the thickest part reads 125°F for medium-rare. The crust should be deep golden.

Tent the lamb with foil and rest for 10 minutes. Slice between the bones into individual chops and serve immediately.