Line an 8 x 8-inch pan with parchment paper and set aside.
In a large mixing bowl, combine the flours, protein powder, sweetener, pumpkin pie spice, and mix well. In a microwave safe bowl or stovetop, heat your peanut butter with your maple syrup until combined.
Pour your wet mixture, vanilla extract, pumpkin, and milk to the dry mixture, and mix well. If the batter is too thick, add extra milk.
Transfer the batter into the lined pan and refrigerate for at least 30 minutes, to firm up. Once firm, cut into bars.
* Depending on the brand of coconut flour and/or protein powder, you may need more milk.TO STORE: Protein bars are best stored in the refrigerator, so they remain firm and chewy. They will keep fresh for up to 1 month. TO FREEZE: Individually wrap protein bars in parchment paper, and place them in small ziplock bags for a quick grab and go snack. Store them in the freezer for up to 6 months.