Soak the chickpeas overnight in a large bowl of water.
In a mixing bowl, combine the drained chickpeas, spices, lemon zest, herbs and chickpea flour. Season with salt and pepper (you can add a pinch or two of cayenne, if you like a bit of heat).
Put half of the mixture into a food processor and whiz, scraping down the sides of the food processor as necessary. When you get a textured mixture, resembling couscous, transfer it into a bowl.
Repeat with the remaining chickpea mix, then combine well the two mixtures. Cover the bowl and chill for 2 hours.
Add the baking powder to the mixture. Using a spoon, form small patties or balls from the mixture - if it falls apart, add more chickpea flour to it. Put the falafels on a plate.
Heat some oil in a small, deep pan (the depth should be approx. 3cm).
Fry 4-5 falafels at a time for about 2-3 minutes each side, until golden brown. Add more oil to the pan as necessary.
Transfer the falafels onto a plate, lined with paper kitchen towels.
Serve with salad, condiments, flatbread etc of your choice.