In a large saucepan, melt the butter. Add the onion and cook over moderate heat until softened, about 4 minutes. Add the lamb, garlic, cinnamon, cardamom and allspice and cook, stirring, until the lamb is no longer pink and the liquid has evaporated, about 4 minutes. Add the rice and chickpeas along with 2 teaspoons of salt and a pinch of pepper and cook, stirring, until evenly coated. Add the stock and water and bring to a boil. Cover and cook over low heat until the rice is tender, about 20 minutes. Remove from the heat, cover and let stand for 10 minutes.
Meanwhile, heat the oil in a small skillet. Add the pine nuts and cook over moderate heat, stirring constantly, until browned, about 4 minutes. Transfer the pine nuts to a plate and season with salt.
Fluff the rice and transfer it to a bowl. Sprinkle the toasted pine nuts over the dressing and serve.