From the previous night, we put the chickpeas in a bowl and pour double the amount of water, enough to cover them well. Let them soak. The next day drain them and put them on a towel or kitchen paper to dry well.
Put the coriander and cumin seeds in a mortar or spice grinder (if you have one) and grind them until they become powder.
Put the chickpeas in a blender and grind them. Add the onions, fresh parsley, coriander, and garlic. Grind and add the ground dry coriander and cumin, baking powder, lemon juice, salt, black pepper and grind well. Add the breadcrumbs and grind until we have a cohesive mixture. Put it in a bowl, cover it, and put it in the refrigerator for 30 minutes.
Take some of the mixture and shape it into balls (like meatballs, about 25g each). Press a little in the middle and place them on a disk. Put plenty of oil in a pan to heat up. It should cover the falafel balls up to the middle.
Fry the falafel balls until they turn golden brown on both sides. Serve with tahini, lemon, and garnish with parsley.