Preheat the oven to 350°F.
Line an 8x8 square baking dish with parchment, letting the ends overhang to use as "handles" later.
In a medium mixing bowl, whisk together the flour, flax, pumpkin pie spice, baking soda, and salt.
In a large mixing bowl, whisk together the pumpkin purée, coconut sugar, cashew butter, and vanilla extract.
Pour the dry into the wet and stir to combine.
Add the chocolate chips and stir to incorporate. The mixture will be thick like traditional cookie dough.
Press the mixture into the prepared baking dish. Pro tip: slightly dampen your hands so the batter doesn't stick to your hands.
Bake for 25 to 28 minutes until a toothpick inserted in the center comes out clean.
Cool in the pan on a wire rack until cool to the touch. Using the parchment "handles" lift the whole thing out of the pan and place on the wire rack to cool completely.
Once cool, cut into squares and enjoy!