Mustard-Rubbed Lamb Rack with Apple Mint “Marmalade”

2 frenched Australian racks of lamb (about 2 1/2 pounds total)
Mint sprigs, for garnish
RUB
3 tablespoons whole-grain mustard
2 tablespoons prepared horseradish
2 teaspoons kosher salt
1 teaspoon coarsely ground black pepper
4 garlic cloves,minced or pressed through a garlic press
1 tablespoon minced fresh thyme
1 tablespoon olive oil
MARMALADE
1 tablespoon butter
1 large unpeeled green apple, cored and coarsely grated
1 tablespoon cider vinegar
1/2 cup red pepper jelly
1 tablespoon minced fresh mint
1. There should be only a thin layer of fat over the meaty side of the lamb racks; if too thick, trim fat carefully with a sharp knife.
2. To prepare the rub, place all ingredients in a small bowl and mix to a paste. Dry lamb well with paper towels, then smear rub on meaty parts.
Let sit at room temperature for 20 minutes.
3. To prepare the marmalade,melt butter in a sauté pan over medium-high heat. Add apple and sauté for 4 minutes, or until just tender. Add vinegar, jelly and mint, bring to a boil, and boil for 2 minutes, or until it has the consistency of chutney. Let cool.
4. Meanwhile, preheat oven to 450°F. In a shallow roasting pan, set lamb racks flat,meaty side up. Roast for 20 minutes, or until internal temperature is 135-140°F (medium-rare), or to the doneness you like.
5. Remove from oven, loosely tent with foil and let stand for 5 minutes.
Carve into chops, cutting between the bones.
6. Serve 3-4 chops per person. Dollop with marmalade and garnish with mint.
Makes 4 servings.