Preheat the oven to 375 degrees and lightly oil a large 12" cast iron or other oven safe skillet.
In a large food processor, process the dates, maple syrup, tahini, vanilla extract, water, and a pinch of salt until completely smooth. See photo in post for reference. There should be no chunks at all and resemble a caramel paste.
Next, add in the thoroughly rinsed chickpeas, oat flour, and baking powder and process again until completely smooth. You do not want any chunks of chickpeas!
Lastly fold in the chocolate chips to the chickpea cookie dough batter.
Press the batter into the skillet until flat and evenly covering the bottom of the skillet. To help with this you can oil your hands a bit or oil a spatula.
Bake for 20-25 minutes. Optional: broil the skillet cookie for the last 2 minutes to give the top nice color.
Serve immediately from the oven with scoops of your favorite vegan ice cream.
Notes
You need a good, large food processor for this recipe. If it is not strong enough, you may not be able to get your cookie dough completely smooth and having chunks of chickpea in this batter will not be pleasant. This is the model I use.
This recipe is absolutely best served fresh, but you can store leftovers in the refrigerator for up to 3 days. Reheat in the microwave.
I make my own oat flour by blending the amount of oats I need in my Vitamix for 10-15 seconds or until a fine powder. You can buy oat flour if you do not have a high speed blender here.