Preheat your oven to 375°F and lightly grease a 16-ounce ramekin or small baking dish with the coconut oil.
In a medium bowl, mash the banana until it reaches a smooth consistency, then stir in the almond flour, cinnamon, and vanilla extract.
In a separate large, clean glass bowl, combine the egg whites, cream of tartar, and sea salt.
Using a hand mixer or stand mixer, beat the egg white mixture on high speed until stiff, glossy peaks form.
Gently fold one-third of the whipped egg whites into the banana base to lighten the texture.
Carefully fold in the remaining egg whites using a spatula, using a light hand to keep the mixture voluminous and airy.
Transfer the batter into the prepared baking dish and bake for 15 to 18 minutes until the soufflé has risen and the top is lightly browned.
Serve immediately while warm to enjoy the delicate, cloud-like texture.