Place rack in upper third of oven and preheat oven to 180°C.
Line a 12-cup muffin tin with paper or foil liners, or lightly grease with cooking spray.
Mash bananas in the bottom of a large bowl until mostly smooth. Whisk in the egg, then the yogurt and oil. Whisk in the cane sugar, maple syrup, and vanilla. Sprinkle the baking soda, salt, and cinnamon over the top, then stir until combined. Gently stir in the flour until barely combined, then fold in the walnuts.
Scoop the mixture into the prepared muffin tins, filling them nearly to the top. Bake for 20-22 minutes, until a toothpick inserted in the center comes out clean and the muffins spring back lightly when touched in the center.