Mash a banana, mix with oats and protein powder, bake. Three ingredients, high protein cookies. They're not fancy, but they disappear fast.
Preheat the oven to 350°F and line a baking sheet with parchment paper.
Mash the ripe banana thoroughly in a medium bowl to ensure a smooth texture.
Add rolled oats, protein powder, cinnamon, and a pinch of salt to the mashed banana, then mix until a cohesive dough forms.
Scoop the dough onto the baking sheet in small rounds, pressing each to about 1/2 inch thick for even baking.
Bake for 18–20 minutes, watching closely after 15 minutes to prevent overbrowning; cookies are done when firm and lightly golden.