Preheat your oven to 350°F (175°C). Grease and line a 9x5-inch loaf pan with parchment paper or lightly flour it for easy removal.
In a large bowl, cream together the softened butter and ¾ cup sugar until light and fluffy. Add the eggs one at a time, beating well after each. Stir in the vanilla extract.
Mix in the mashed bananas until fully combined. The mixture may look slightly curdled—this is normal.
In a separate bowl, whisk together the flour, baking soda, baking powder, salt, and cinnamon (if using). Gradually add the dry ingredients to the banana mixture and stir just until combined. Do not overmix.
Pour the batter into the prepared loaf pan and smooth the top. Sprinkle the remaining 2 tablespoons of granulated sugar evenly over the top. This creates a lightly crisp, cookie-like crust.