Preheat your oven to 450°F (230°C) and position the rack in the center.

Allow the lamb to come to room temperature for 30 minutes before cooking. Pat dry with paper towels.

Season the racks generously with salt and pepper on all sides.

Heat olive oil in a large oven-safe skillet over medium-high heat. When hot, add the lamb racks meat-side down and sear until golden brown, about 2-3 minutes. Flip and sear the other side for another 2-3 minutes.

Remove the skillet from heat. Brush the meat side of each rack with Dijon mustard.

In a bowl, combine bread crumbs, minced garlic, chopped rosemary, thyme, lemon zest, and melted butter. Mix well until the mixture holds together when pressed.

Press the herb mixture firmly onto the mustard-coated side of each rack, creating an even crust.

Transfer the skillet to the preheated oven and roast for 18-20 minutes for medium-rare (internal temperature of 125°F to 130°F) or 20-25 minutes for medium (internal temperature of 135°F to 140°F).

Remove from the oven and tent loosely with foil. Let the lamb rest for 10 minutes before slicing between the bones to serve.