Drain chickpeas and grind them, along with cumin, coriander, salt, allspice, and pepper for a minute or two in the food processor, until it's a fine paste. Return ground chickpeas to their soaking container and unwashed food processor bowl back to the machine and add remaining ingredients, except baking powder, and process until finely minced. Add herb mixture to chickpeas; mix to thoroughly combine. (Can be covered and refrigerated for a couple of days.)