Preheat the oven to 350 degrees. Line 2 large baking sheets with parchment paper and set aside.

Place the peanut butter, flax seed, molasses, and cinnamon in a large mixing bowl and stir until well combined. Mix the egg in thoroughly. Gradually stir in the brown rice flour until fully incorporated, adding enough water to form a cohesive dough. (Dough will be very stiff and dry so your hands might work better than a spoon.)

Roll dough out into 1/4-inch thick and use a 1.5-inch cookie cutter to cut out desired shapes. (You can use any size cookie cutter but you’ll have to adjust your baking time.) Gather scraps and re-roll as necessary. Arrange cut out cookies on the prepared baking sheets. (The cookies won’t spread much so you can place them fairly close to each other.) Bake 25 to 40 minutes, until the cookies are thoroughly dried out. Cool completely on baking sheets, then store in an airtight container.