1 . Stage
Heat waffle iron and grease with cooking spray.
2 . Stage
In a large bowl, whisk together flour, baking soda, and salt. In another large bowl, stir together melted butter, sugar, egg, egg yolk, sour cream, and vanilla. Add mashed bananas and stir until combined. Gradually add dry ingredients to wet ingredients until just combined. Fold in chocolate chips.
3 . Stage
Add 1 cup batter to waffle iron. Close and cook until golden on both sides. Transfer waffle to a plate and repeat with remaining batter. Serve with maple syrup.