Boil potatoes, remove it from the hot water immediately. Peel and mash it. Blanch the spinach in hot water for 1 minute, remove from the hot water and squeeze the water from the spinach. Grind it and make a thick paste. If required add some mashed potato to spinach and then grind. In a mixing bowl, add boiled and mashed potato, spinach paste, bread crumbs, corn starch, ginger & garlic paste, green chili and salt to taste. Mix all ingredients very well and make a nice green dough (if dough is watery, add more bread crumbs).