Preheat your oven to 350°F and line a baking sheet with parchment paper for easy cleanup.
Place the rolled oats into a high-speed blender and pulse until they reach a fine, flour-like consistency.
In a medium mixing bowl, whisk together the egg, natural peanut butter, Greek yogurt, and vanilla extract until the mixture is completely smooth.
Gradually fold in the oat flour, vanilla protein powder, baking powder, ground cinnamon, and sea salt until a thick, uniform dough forms.
Divide the dough into four equal portions, roll them into balls, and place them on the prepared baking sheet.
Use a fork to gently press down on each ball, creating a crosshatch pattern and flattening them to about half an inch thick.
Bake for 8 to 10 minutes until the edges are lightly golden but the centers still feel soft to the touch.
Remove from the oven and let the cookies rest on the baking sheet for at least 5 minutes to firm up before enjoying.