Place lamb in a food storage bag. Combine the 7 spices in a small bowl. Sprinkle into the bag and seal bag. Shake and evenly coat the lamb pieces in the spices.
Heat a large, deep skillet over medium-high to high heat. Add 3 tablespoons extra-virgin olive oil, 3 turns of the pan, then the lamb. Sear the lamb and caramelize the meat all over, 5 to 7 minutes. Add the onions and garlic and cook 5 minutes more. Add the dates and 2 cups of chicken stock to the pan and cover. Cook 7 to 8 minutes more to plump the dates and soften the onions. Remove cover and adjust seasonings.
During the last 5 minutes the lamb has to cook, melt butter and toast pine nuts. Add 2 cups stock and bring to a boil. Remove pan from heat, add couscous and cover pan. Let stand 5 minutes. Remove lid and fluff with fork.
Serve lamb over couscous in shallow dishes and garnish with chopped scallions.