Preheat the oven to 180C/350F. Line an 8 x 8-inch pan with parchment paper and set aside.
In a small bowl, add your oat flour, cocoa powder, and salt, and mix well. Set aside. In a separate bowl, whisk together your peanut butter, maple syrup, coconut oil, and granulated sweetener of choice. Whisk together until combined and glossy. Add your eggs and whisk well.
Combine your wet and dry ingredients and mix together until just combined. Fold through your chocolate, if using them. Transfer the brownie batter into the lined pan.
Bake the brownies for 30-35 minutes, or until a skewer comes out clean from the center. Let cool in the pan completely, before slicing.
Notes
TO STORE: Store leftover oat flour brownies in an airtight container in the refrigerator for up to two weeks. TO FREEZE: Transfer cooled brownies to a freezer-safe container and freeze for up to six months.