Preheat your oven to 375°F and lightly grease a small oven-safe baking dish or ramekin with the coconut oil.
In a mixing bowl, whisk together the liquid egg whites, non-fat Greek yogurt, vanilla extract, and maple syrup until the mixture is smooth and well combined.
Fold in the rolled oats, baking powder, ground cinnamon, and sea salt, stirring until the oats are fully submerged in the liquid.
Pour the oat mixture into the prepared baking dish, smoothing the top with a spatula.
Slice the half banana into thin rounds and arrange them in a single layer across the top of the oatmeal mixture.
Place the dish in the oven and bake for 25 to 30 minutes, or until the center is set and no longer giggles when moved.
Switch the oven to the broiler setting for the last 1 to 2 minutes of cooking to allow the banana slices to become golden and caramelized.
Remove from the oven and let the bake sit for 5 minutes to firm up before enjoying warm.