Preheat the oven to 350°F / 175°C.
Add the cottage cheese, Greek yogurt, banana, eggs, and oat flour to a blender.
Blend until completely smooth.
Let the batter sit for 5–10 minutes, so the oat flour can absorb some moisture.
Pour into a lined small baking dish or a 6-inch pan.
Add berries or fruit on top, if using.
Bake for 35–45 minutes, or until the edges are set and the center is only slightly soft.
Let it cool completely, then refrigerate for 2–3 hours, or ideally overnight, before slicing.
