oil for frying (use one with a high smoke point)(I use avocado, you can also use canola)
Place the garbanzo beans in a large bowl, cover them with 3 inches of water, cover and let them soak for 20-24 hours (they will expand to about 5 cups). Note: If the don't soak long enough the falafel will be crumbly and fall apart. Rinse and drain.
Heat a small, heavy skillet over medium-high heat and dry roast the whole cumin and whole coriander seeds just until they become very fragrant. Be careful not to scorch or burn them or they will be bitter. Once fully cooled grind them in a coffee/spice grinder or mortar and pestle.
Place the ground spices with all the falafel ingredients in a large food processor and pulse the ingredients until well ground but but not a smooth paste, it should be chunky (over-pulsing it will cause the falafel to fall apart). Refrigerate for at least one hour (this mixture can be prepared well in advance).
Form the falafels into roughly the size of golf balls. You'll need to compress the mixture together firmly and carefully transfer the balls to a plate until ready to use. (Keep in mind, they won't have the texture of dough or hold together like dough. They'll be pretty loose and delicate but will hold together once they're fried.)Fill a heavy skillet about 1 1/2 to 2 inches deep with oil.The temperature of the oil is key for frying falafel. They need to start sizzling immediately upon impact so they don't become oil-logged and fall apart, but you also don't want them to burn. I recommend using an instant-read thermometer to check the temperature. Aim for a temperature between 360 and 375 degrees F. Once the oil is up to temperature, carefully place the falafel in the pan, a few at a time (don't overcrowd), leaving adequate space between them so they brown properly. (We recommend you try it with one falafel first to make sure the temperature is right.) Fry the falafel until a deep golden brown, about 2-3 minutes on each side, very carefully turning them over to fry the other side. Use a slotted spoon to remove them from the oil and set them on a plate lined with paper towels to drain. *Bring the oil up to the proper temperature before adding a second batch.
For Serving: To make falafel pita, spread some homemade creamy hummus inside the pita, layer some lettuce, tomatoes, onions, pickles, and falafel - and anything else you'd like to throw in there! Then top it with some of the yogurt sauce (we recommend our Preserved Lemon Cilantro Sauce) and a drizzle of tahini sauce (see below).