Soak the chickpeas in a bowl of water overnight. The next day, drain them and measure out 2.5 cupful. (Keep the rest for hummus or other meals).
Put the spinach, onion, garlic and a handful of chickpeas in a food processor and pulse until it becomes a rough paste, then gradually add the rest of the chickpeas. Add the herbs, spices, slat and chai seeds and whizz until you get a textured mixture resembling couscous.
Transfer the mixture into a bowl and rest in the fridge for an hour or so.
When you’re ready to make the falafels, take the bowl out of the fridge and mix in the baking powder. Form a ping pong sized ball and test it - if it’s not sticking together, add some chickpea flour to the mixture (about 2 tbsps). Shape about 18-20 balls of the mixture, then flatten them slightly between your palms into patties (if you prefer this shape).
Pour some oil in a small, deep pan - it should be about 2-3 cm deep. When hot, add 5-6 falafels and fry them over medium-high heat for 2-3 minutes on each side.
Transfer the falafels to a plate, lined with paper kitchen towels.
Serve them lukewarm with condiments of your choice.