2 (1 1/4 pound) trimmed and frenched
single rack of lamb (14 or 16 ribs)
2 tablespoon unsalted butter
2 teaspoon lemon zest, grated
4 teaspoons fresh tarragon, minced or
3/4 teaspoon dried, crumbled, plus tarragon sprigs for garnish
2 tablespoon fresh lemon juice
Salt and pepper, to taste

Heat an ovenproof skillet over moderately high heat until it is hot and in it brown the lamb, seasoned with salt and pepper, turning it, for 4 minutes, or until the sides and the ends are browned evenly. Pour off any fat from the skillet, arrange the lamb, fat and meat side up, and bake it in the middle of a preheated 475 degree oven for 15 minutes, or until a meat thermometer registers 130 degrees for medium-rare meat.

Transfer the lamb carefully to a cutting board, and let it stand, uncovered, for 10 minutes. While the lamb is standing, in a small saucepan melt the butter and stir in the zest, the minced tarragon, the lemon juice and salt and pepper to taste. Cut the lamb between the ribs and divide it between 4 plates. Garnish the lamb with the tarragon sprigs and serve it with the sauce.