Prep the Lamb

Adjust the oven rack to the middle position and heat the oven to 250°F. Using a sharp knife, score the fat cap in a crosshatch pattern, making ½‑inch‑spaced slits that cut through the fat but not into the meat.

Mix the salt and cumin together. Rub about ¾ teaspoon of the mixture over each rack, making sure to work it into the slits. Reserve the remaining seasoning.

Slow Roast

Place the racks bone‑side down on a wire rack set inside a rimmed baking sheet. Roast until the internal temperature reaches 125°F for medium‑rare or 130°F for medium, about 1 hour 5 minutes to 1 hour 25 minutes.

Sear for a Crust

Heat the vegetable oil in a 12‑inch skillet over high heat until just smoking. Add one rack, bone‑side up, and sear until the fat cap is deeply browned, 1–2 minutes. Transfer to a carving board. Pour off all but 1 teaspoon of fat and repeat with the second rack.

Rest and Finish

Tent both racks loosely with foil and let rest for 20 minutes. Slice between the bones to separate the chops, drizzle with balsamic glaze, and serve. Pass the remaining salt‑cumin mixture at the table.