Preheat your oven to 350°F (175°C). Grease and flour a 10-inch loaf pan or use parchment paper for easy removal.

In a bowl, mash the bananas until smooth or slightly chunky, depending on your preference. Set aside.

In a large bowl, cream the softened butter with the dark brown sugar. Mix it together until the mixture becomes light and fluffy. This should take around 3-5 minutes. The air incorporated during this step is crucial for a light texture.

Mix in the eggs one at a time, making sure to fully incorporate each one before adding the next. Finally, stir in the vanilla extract.

In a separate bowl, combine the flour, baking powder, baking soda, sea salt, and ground cinnamon. Whisk together to combine.

Gradually add the dry mixture to the wet mixture, alternating with the mashed bananas. Start and end with the dry ingredients, mixing until just combined. Be careful not to overmix. Fold in the chopped walnuts at this point.

Pour the batter into the prepared loaf pan. Bake for 60-70 minutes or until a toothpick inserted in the center comes out clean. The top should be a beautiful golden brown when done.

Once baked, allow the cake to sit in the pan for about 10 minutes. Then, transfer it to a cooling rack to cool completely.

While the cake cools, prepare the glaze. In a saucepan, melt the butter with the dark brown sugar over low heat.

Stir in the maple syrup and heavy whipping cream. When it’s fully combined, remove from heat and stir in vanilla extract. Allow it to cool slightly before drizzling over the cake.