Preheat oven to 375°F and line a muffin tin with liners in every other cavity.
In a medium bowl, mix mashed bananas, almond butter, melted coconut oil, coconut sugar, vanilla extract, and cinnamon.
Sift in all-purpose flour, baking soda, and salt. Fold until almost combined, then add walnuts.
Divide the batter into the prepared muffin tins. Sprinkle coarse sugar and top with walnuts.
Bake for 23-25 minutes until a toothpick inserted in the center comes out clean.
Let cool for 15 minutes before enjoying!