Soak the chickpeas in plenty of water for 12-24 hours, changing the water several times.
Drain the chickpeas thoroughly.
Add the chickpeas, onion, garlic, parsley, salt, black pepper, turmeric, and ground coriander seeds to a food processor.
Process until the ingredients are finely combined but not completely smooth.
Transfer the mixture to a bowl and gently knead it.
If the mixture is too loose, add 1 tablespoon of chickpea flour and add more only if necessary.
Shape the mixture into small balls about the size of a walnut.
Heat oil in a deep pan.
Fry the falafel in small batches until golden brown and crispy.
Remove and place on paper towels to absorb excess oil.
Serve warm with bread, fresh vegetables, pickles, or your favorite sauce.