Soak half the apricots in 500ml boiling water for 10 minutes. Drain, reserving the water. Tip the apricots into a blender, add the garlic, cinnamon, cumin, and orange zest and juice. Season and blend well to make a paste.
Preheat the oven to 160°C, gas mark 3. Mix the soaking water with the honey. Put the lamb in a large roasting tin and coat with the apricot paste. Arrange the onions and remaining apricots around the lamb, then pour the soaking water over the onions and apricots. Cover with foil and cook for 4 hours.
Remove the lamb from the oven, discard the foil and increase the heat to 200°C, gas mark 6. Drain the liquid from the tin and pour into a small pan. Return the lamb to the oven. Bring the liquid to the boil, reduce the heat slightly and cook for 10-15 minutes until thick and syrupy. Pour into a serving bowl.
Remove the lamb from the oven and shred at the table. Scatter over the pomegranate seeds, and serve the apricot glaze, roasted onions and apricots on the side.