Preheat the oven to 325 degrees F. Line a 8x8-inch baking dish with parchment paper and/or spray with nonstick cooking spray.

For the Cookie Layer: In a large mixing bowl, combine the oat flour, coconut flour, brown sugar, sweetener, baking soda, and salt. Mix until the ingredients are combined and there are no clumps. Then add the melted butter, milk, and vanilla and mix with a silicone spatular until all the dry ingredients are incorporated and you h ave a ball of dough. Fold the chocolate chips into the cookie dough. Then place in the freezer for 5 minutes to thicken while you make brownie batter.

For the Brownie Layer: In a medium-sized bowl, add the protein powder, flour, cocoa powder, sweetener, baking powder and baking soda. Combine with a whisk until there are no clumps. Add the pumpkin, butter, milk, and melted chocolate. Using a hand or stand mixer, mix to combine.

Assembly: Press cookie dough into the bottom of the prepared baking dish in a smooth layer. Place the Oreos on top of the cookie dough layer. Then, add the brownie batter on top of the Oreo cookie layer. Then, add the brownie batter on top of the Oreo cookie layer. Spread evenly across with a silicone spatula.

Bake for 32-36 minutes, or until a toothpick inserted in the center comes out mostly clean. It's okay if it's still a little gooey when you take it out, it will continue to cook some more in the pan and you don't want to over-bake these!

Let brownies cool in the pan for 15 minutes. If you wish to eat warm, cut into bars. If you prefer them cold, go ahead and store them in the fridge, covered, and cut into bars when you are ready to eat. They will be easier to cut the longer they have set.