Ingredients

• 1 tablespoon butter
• 2 tablespoons tomato paste
• 6 garlic cloves, minced
• 2 teaspoons chopped fresh thyme
• 2 cups dry red wine
• 1 cup canned beef broth
• 1 cup canned low-salt chicken broth
• 2 tablespoons shelled cardamom seeds
• 2 1 1/4- to 1 1/2-pound racks of lamb, trimmed
• 2 tablespoons olive oil
• 1/4 cup (1/2 stick) chilled unsalted butter, cut into pieces
• 4 teaspoons coarse-grained mustard
• Mashed Sweet Potatoes with Maple Syrup

Instructions

1. Melt 1 tablespoon butter in heavy medium saucepan over medium-high heat. Add tomato paste, garlic and thyme; sauté 1 minute. Add wine and boil until reduced by half, about 8 minutes. Add both broths; boil until reduced to 1 1/4 cups, about 10 minutes. (Can be made 1 day ahead. Cover and refrigerate.)
2. For lamb: Preheat oven to 450 °F. Toast cardamom seeds in heavy small skillet over medium heat until fragrant, about 2 minutes. Cool. Transfer to spice grinder; grind coarsely. Sprinkle lamb with cardamom, salt and pepper. Heat oil in heavy large skillet over high heat. Add 1 lamb rack; sear until brown, turning occasionally, about 6 minutes. Transfer lamb, meat side up, to baking sheet. Repeat with second lamb rack. Roast until meat thermometer inserted into center registers 125°F for medium-rare, about 18 minutes. Let stand 5 minutes. Cut lamb between bones into chops. Bring sauce to simmer. Reduce heat to low. Add butter and mustard; whisk just until butter melts. Season with pepper. Spoon sauce onto plates. Top with sweet potatoes and lamb and serve.
3. Preheat oven to 450 °F. Toast cardamom seeds in heavy small skillet over medium heat until fragrant, about 2 minutes. Cool. Transfer to spice grinder; grind coarsely.
4. Sprinkle lamb with cardamom, salt and pepper. Heat oil in heavy large skillet over high heat. Add 1 lamb rack; sear until brown, turning occasionally, about 6 minutes. Transfer lamb, meat side up, to baking sheet. Repeat with second lamb rack. Roast until meat thermometer inserted into center registers 125°F for medium-rare, about 18 minutes. Let stand 5 minutes. Cut lamb between bones into chops.
5. Bring sauce to simmer. Reduce heat to low. Add butter and mustard; whisk just until butter melts. Season with pepper. Spoon sauce onto plates. Top with sweet potatoes and lamb and serve.