The first thing you need to do is soak your chickpeas and lentils. I throw them all in a bowl together and add the tablespoon of apple cider vinegar or lemon juice. Let them sit overnight, covered, on your counter.
The next day, strain the lentils and chickpeas. You will have enough to make a few flatbreads, so reserve a cup of them to make your flatbread today. Put the rest in a quart jar covered with filtered water. These will last for quite a while in the fridge.
Now it's time to make the bread. Put a cast iron pan in your oven and turn it on to preheat both the oven and the pan to 375 degrees F.
Put your cup of chickpeas and lentils in the blender along with 1/2 cup of water, 1tbsp Olive oil, and a generous pinch of good salt. Blend it like crazy until it is a smooth liquid.
By this time your oven will probably be ready. When it is preheated, take your cast iron pan out, pour some olive oil in, and swirl it around to coat the pan. Pour in the batter. You may have to flatten it out a little, depending on how thick it is.
Bake for 25-30 minutes, until it is brown and crispy on the edges. Let it cool and then remove it from the pan and serve.
If you'd like a thinner flatbread (more like a wrap), you can slightly increase the amount of water in the blender. If you'd like it thicker (eg. for pizza) then slightly decrease it.You may also want to add in various spices and herbs or other flavors, such as cheese, garlic powder, or dried parsley.