Gather all ingredients.

Place dried chickpeas into a large container and cover with several inches of cool water; let stand 12 to 24 hours. Drain.

Blend chickpeas, onion, parsley, garlic, flour, lemon juice, salt, cumin, coriander, baking soda, and cayenne pepper together in a food processor, scraping down the sides of the bowl as necessary, until mixture is finely ground and holds together when pressed.

Transfer falafel mixture to a bowl, cover with plastic wrap, and refrigerate until flavors blend, 1 to 2 hours. Heat oil in a deep-fryer or large saucepan to 350 degrees F (175 degrees C).

Divide falafel mixture into 12 portions and roll each with moistened hands to form a ball.

Working in batches, cook falafel balls in hot oil until browned and crispy, about 5 minutes. Transfer to a wire rack to drain.