Lamb Chops with Mashed Sweet Potatoes and Onions

Preparation

1. For sauce:

   Step 1

   Heat oil in heavy large Dutch oven over high heat. Working in batches, add lamb bones; sauté until well browned, stirring often, about 10 minutes. Transfer bones to platter. Add onion and sauté until brown, about 12 minutes. Return bones to Dutch oven. Add both broths, garlic and thyme and bring to boil. Reduce heat, partially cover Dutch oven and simmer 2 hours.

   Step 2

   Strain sauce into heavy small saucepan, pressing hard on solids to release liquid. Discard solids. Boil sauce until reduced to 2/3 cup, about 20 minutes. Spoon fat off surface. Set sauce aside.

2. For Sweet Potatoes:

   Step 3

   Cook sweet potatoes in large pot of boiling salted water until tender, about 13 minutes. Drain. Melt butter in heavy medium skillet over medium-high heat. Add onion and minced thyme and sauté until onion is golden brown, about 10 minutes. Transfer sweet potatoes and onion mixture to processor and puree until almost smooth. Stir in cloves. Season with salt and pepper. (Sauce and sweet potatoes can be prepared 1 day ahead. Cover separately and chill.)

   Step 4

   Season lamb with salt and pepper. Heat 1 tablespoon oil in large skillet over high heat. Working in batches, add lamb; cook to desired doneness, adding more oil to skillet as necessary, about 4 minutes per side for medium-rare.

   Step 5

   Meanwhile, bring sauce to simmer. Rewarm sweet potatoes in medium skillet over low heat, stirring often.

   Step 6

   Place large spoonful of potatoes in center of each of 4 plates. Top each with 2 chops. Spoon sauce over. Garnish with thyme sprigs.