Instructions

  1. Preheat the oven to 475°F.
  2. Season the lamb generously with salt and pepper.
  3. Place a large cast-iron skillet over high heat, when very hot, add the oil and sear one of the racks all over until it is very brown, about 2 minutes per side.
  4. Transfer to a roasting pan fitted with a rack, laying it rounded side up.
  5. Repeat with the remaining rack.
  6. Cover with foil and set aside.
  7. Place the remaining ingredients, except the vinegar, in a food processor.
  8. Add 1/2 tsp salt and 1/4 tsp pepper, and process until it forms a paste.
  9. Press the paste onto the racks.
  10. Roast until desired doneness, 15 min for medium rare.
  11. Allow to rest for 5 min, covered, then carve and serve drizzled with balsamic vinegar.