Preheat your oven to 350°F (175°C). Grease and flour an 8×4-inch loaf pan or line it with parchment paper.

Using a fork, mash the bananas in a bowl until you have 1 ⅓ cups of smooth mashed bananas. Set aside.

In a small bowl, whisk together the all-purpose flour, baking soda, salt, and cinnamon. Set this mixture aside.

In a medium bowl, combine the softened butter, brown sugar, and granulated sugar. Cream them until light and fluffy, about 2 minutes.

Add the eggs one at a time, mixing well after each addition. Then add the vanilla extract and mix until incorporated.

Stir the mashed bananas into the wet mixture until evenly combined.

Add the dry ingredient mixture to the banana mixture. Stir gently just until combined—avoid overmixing to keep the bread tender.

Pour the batter into the prepared loaf pan. Bake for 45 to 60 minutes, or until a toothpick inserted in the center comes out clean.

Let the banana bread cool in the pan for 5 minutes, then remove it from the pan and transfer it to a wire rack to cool completely before slicing.