Preheat oven to 375°F (190°C).

Combine ground cumin, ground coriander, ground cinnamon, paprika, salt, and pepper in a small bowl.

Coat the racks of lamb with olive oil.

Rub the spice mixture evenly over the lamb.

Arrange thinly sliced onion in a roasting pan coated with cooking spray.

Place the spiced lamb racks on top of the onions.

Bake at 375°F (190°C) for 30 minutes, or until a meat thermometer inserted into the thickest part of the lamb registers 130°F (54°C) for medium-rare.

Let the lamb rest for 10 minutes before cutting into chops.

Discard the cooked onions.

In a medium saucepan, combine water, chopped dried plums, ground cumin, ground coriander, ground cinnamon, paprika, salt, and black pepper.

Bring the mixture to a boil over medium heat.

Reduce heat and simmer for 20 minutes, or until the sauce reduces to 2 cups.

Stir in fresh lemon juice.

Serve the plum sauce with the spiced lamb chops.

Garnish with chopped fresh cilantro.