Preheat oven to 350 degrees F and line a bread pan with parchment paper. Whisk together protein, coconut flour, oat fiber, and baking powder in a medium bowl.
Stir in egg whites and plant milk. Once combined, press the batter into the prepared baking dish. Sprinkle with crumbled cookies.
Bake for 15 minutes. Remove from oven and let cool completely before lifting out of the pan, slicing, and storing in the fridge!