Preheat oven to 350℉/176℃ and line two large baking sheets with parchment paper.
Blend the beans and milk until smooth and then transfer the mixture to a large bowl.
Add all the dry ingredients and mix until you have a ball of dough. It will be firm, but softer and stickier than pizza dough.
Divide the dough roughly in half and place each half on your prepared trays, or work on your counter if easier. (Make sure the dough is on parchment paper, and not directly on your tray or counter to prevent sticking.)
Place another sheet of parchment paper over the dough and use a rolling pin to flatten and stretch the dough as evenly and thinly as possible without breaking it. Then remove the parchment paper on top of your dough and smooth out any rough or rounded edges to make them straight with a silicone spatula or your fingers. (This will help with even, uniform crackers, but is not entirely necessary.)
Cut the dough into a grid pattern with a cookie or pizza cutter. Slightly separate each row and column by pushing the edges over with your cutter. This will help crisp up the edges. Then use a fork to prick the dough all over.
Optional: Brush the dough with olive oil and sprinkle with rosemary and extra salt if you'd like.
Bake in your preheated oven for 30-35 minutes, until the edges of your crackers are golden. Remove from the oven, let cool to room temperature, and serve with a dip or as is.
Notes
If you don't have oat flour or chickpea flour on hand, you can make some by grinding oats and/or chickpeas in a high-speed blender. (I use my Vitamix).
The dough will be firm, but softer and stickier than pizza dough. This is normal.
Use TWO sheets of parchment paper (1 below and 1 above the dough) when stretching, to prevent it from sticking to your rolling pin.
Separate the rows of protein crackers AND prick the dough with
If you have leftovers, you may store them at room temperature in a sealed container for up to 5 days. Make sure they are completely cooled before storing.