Yield: 4 servings.
2 racks of lamb (1¼ pounds each), trimmed
Salt and pepper, to taste
2 tablespoons vegetable oil
4 tablespoons unsalted butter, divided
3 teaspoons fresh lemon zest
2 fresh garlic cloves, minced
4 teaspoons fresh tarragon, minced, or ¾ teaspoon dried and crumbled
2 teaspoons fresh mint, minced
3 tablespoons fresh lemon juice
Tarragon sprigs, for garnish
Preheat oven to 425°. Season the lamb with salt and pepper. Heat vegetable oil in an ovenproof skillet over medium-high heat. Place the lamb in the skillet to brown, turning it after 3 minutes, or when the sides and ends are browned evenly. Remove the lamb and pour off any fat from the skillet. Replace the lamb, fat and meat side up, and bake it on the middle oven rack for 15 minutes, or until a meat thermometer registers 130°, for medium-rare meat. Transfer the lamb to a cutting board and let it rest, uncovered, for 10 minutes.
In a small saucepan, melt the butter and stir in the zest, minced tarragon, mint, lemon juice, and garlic. Add salt and pepper to taste. Cut the lamb between the ribs and divide it among 4 plates. Drizzle the sauce over the lamb and garnish with a tarragon sprig.
Note: For a richer flavor, use 2 tablespoons of butter and 2 tablespoons of fat from the lamb when making the sauce.