Middle Eastern Roast Lamb With Tahini Sauce

Name: Middle Eastern Roast Lamb With Tahini Sauce
Ingredients: 1 teaspoon paprika; 1 teaspoon ground cinnamon; 1/2 cup tahini , (see Tip); 1/4 cup water; 1 teaspoon ground cumin; 1/2 cup minced fresh parsley; 1 4-pound boneless leg of lamb, butterflied and trimmed (see Tip); 8 medium cloves garlic, divided; 2 tablespoons extra-virgin olive oil; 2 1/2 teaspoons salt, divided; 1/2 teaspoon freshly ground pepper; 1/2 cup lemon juice; 1 1/2 teaspoons ground mace; 6 tablespoons nonfat plain yogurt, preferably Greek-style; 1/2 teaspoon cayenne pepper; 1 teaspoon ground cardamom