1. Preheat oven to 375°.
2. To prepare lamb, combine the first 6 ingredients. Coat lamb with oil. Rub spice mixture on lamb.
3. Arrange onion in a roasting pan coated with cooking spray; top with lamb. Bake at 375° for 30 minutes or until a thermometer inserted in thickest part of lamb registers 130°. Let stand 10 minutes. Cut lamb into chops. Discard onions.
4. To prepare sauce, combine 1 3/4 cups water and next 7 ingredients in a medium saucepan; bring to a boil. Reduce heat to medium; simmer 20 minutes or until sauce measures 2 cups. Stir in juice. Serve sauce with lamb. Sprinkle lamb with cilantro.
Wine Match: A big red has enough body to stand up to the meaty lamb, and its fruit marries well with the plum. Sonoma's Dry Creek Vineyard's Heritage Zinfandel 2009 ($19) is juicy with undertones of clove and pepper that draw out the aromatics. --Gretchen Roberts