Rinse (uncooked) chickpeas in a fine mesh strainer and add to a large pot. Cover with 2 inches water and bring to a boil over high heat. Boil for 1 minute, then cover, remove from heat, and let set for 1 hour. Then drain and lightly rinse and dry thoroughly (method from the Kitchn).
In the meantime, add parsley, onion and garlic to a food processor. Mix until well processed. Set aside.
Once the chickpeas are slightly cooled and dried, add to the food processor, along with gluten free oat flour, salt, cumin, cardamom, coriander, cayenne (optional). Mix to combine thoroughly, scraping down sides as needed. This may take up to 4-5 minutes to fully incorporate all of the spices and herbs. You're looking for a near paste with only very small bits of chickpeas and herbs.
Sample a small bit and adjust spices/salt/herbs as needed.
Scoop out 1 1/2 Tbsp amounts and form into small discs using your hands. If the falafel isn't sticking together the mixture may need to be blended more thoroughly, or dusted with a bit more oat flour if too wet.
Once your falafels are formed (~24 total), heat a large metal or cast iron skillet over medium/ medium-high heat. Once hot, add enough oil to create a thin layer on the bottom of the pan and wait 1-2 minutes for the oil to heat up. Then place only as many falafel as will fit comfortably in the pan and cook 2-3 minutes on each side. Once the bottom side is browned, flip gently as they can be fragile. Continue until all falafel are cooked, or place ones you are not eating on a sheet pan in the freezer. Once frozen take out and store in an airtight container.
These falafel are delicious on their own with hummus, garlic dill sauce, or tahini dressing. I also love garnishing them with chili garlic sauce for heat. Serve over greens, in pita, or enjoy as is!