In a large pot of water, boil the chickpeas until tender, about 1 hour.
Preheat oven to 425 F.
Toss the carrots with 1 tablespoon of the olive oil, 1/8 teaspoon salt and raz el hanout. Roast for 15 minutes. Add half of the chickpeas and roast for another 10 minutes.
In a saucepan, heat remaining oil. Add onion and ginger. Saute until golden. Add the rest of the chickpeas, sugar, rosewater and stock. Bring to a boil. Add watercress and spinach. Cook for a few minutes until the leaves wilt.
Leave it to cool for a few minutes and transfer it to a blender or use an immersion blender to puree the soup. Add salt and simmer for another 2-3 minutes.
To serve, place pureed soup in a bowl and add the roasted carrots & chickpeas.
Garnish with a little of the sumac.
Notes
You can also substitute cooking the chickpeas with canned chickpeas.