PREHEAT oven to 350 and grease 6 muffin tins with non-stick olive oil spray or coconut oil. In a small mixing bowl, whisk together coconut flour, Swerve, baking powder, cinnamon and sea salt. In a medium mixing bowl, beat egg whites until soft peaks form. Set aside.
IN a separate mixing bowl, mash banana and use a hand mixer to beat in 2 eggs, coconut milk, and butter until smooth. Pour wet ingredients into dry and mix on low speed to combine. Stir in 1/2 of walnuts.
USE a spatula to gently fold egg whites into batter. Using a 1/3 measuring cup, pour batter into prepared muffin tins. Sprinkle with remaining walnuts. Bake 25-30 minutes. Cool 10 minutes.