Preheat oven to 350 degrees. Sift all dry ingredients into a large mixing bowl and add milk and water. Stir to mix well. The resulting mixture will be a very wet “dough” (so wet, you can hardly call it a dough). Cut two sheets of parchment paper to fit two baking sheets, and set one sheet of parchment paper on the counter where you’ll be rolling — you won’t be able to transfer it without this
Glop half of the “dough” out onto the sheet of parchment paper and flatten it by hand. Place a piece of plastic wrap over the dough and “roll” it out (your rolling pin will almost just be smooshing it out into place) EXTREMELY THIN, almost transparent in some places. It will look like a giant bran flake — super fun!
Remove the plastic wrap and transfer the parchment carefully to a baking sheet. Cook for 10 minutes, but check often after just 5, because such a thin dough can easily burn. You’re looking for a thin, leathery cracker that is crunchy at the edges. When it’s done, remove it and allow it to cool completely. While it cools, repeat the process with the other half of the dough.