Finely chop the onion and garlic.
In a mixing bowl, combine the drained chickpeas, garlic, onion, spices, salt pepper and pastes. Put the mixture into a food processor and whiz, scraping down the sides of the food processor as necessary.
Add the black beans and fresh coriander leaves. Pulse again until you get a sticky, coarse texture. Transfer the mixture into a bowl.
Add the flaxseed paste and the chickpea flour. Combine well, cover the bowl and chill for 2 hours.
When you’re ready to cook the falafels, take the mixture out of the fridge. Form small patties. If the mixture doesn’t stick together properly, add more chickpea flour.
Heat some grapeseed oil in a small, deep pan - the depth of the oil should be about 3 cm. Fry 4-5 patties at a time, for about 2-3 minutes on each side, until golden brown.
Transfer the falafels onto a plate, lined with paper kitchen towels.
Fry more falafels, using up the mixture. Add more oil to the pan as necessary.