Mix the ground flaxseed with warm water in a small bowl and let it sit until it forms a gel-like consistency (about 5 minutes).
Mix Dry Ingredients: In a medium bowl, whisk together the oat flour, chickpea flour, tapioca starch, baking powder, and salt.
Combine Wet Ingredients: In another bowl, mix applesauce, warm water, apple cider vinegar, and the flaxseed mixture.
Make the Dough: Combine wet and dry ingredients, stirring until a slightly sticky dough forms. If the dough is too dry, add warm water gradually until pliable; if it's too wet, mix in a bit of flour or tapioca starch until it reaches a manageable consistency. Let it rest for 10 minutes, and cover it with a wet kitchen towel to hydrate fully.
Form the Flatbreads: Divide the dough into six equal portions. On parchment paper or a clean surface, lightly dusted with extra oat flour, roll each portion into a ¼-inch thick flatbread.
Cook: Heat a non-stick skillet or cast-iron pan (the best option) over medium heat. Keep uncooked flatbreads covered with a damp kitchen towel to prevent drying. Cook each flatbread for 3-4 minutes per side until golden and cooked through.
Serve: Serve warm, topped with your favorite spreads, veggies, or dips!