Preheat your oven to 350°F (175°C) and prepare an 8x4-inch loaf pan by greasing it or lining it with parchment paper.

Mash the overripe bananas in a medium mixing bowl until smooth with some texture; aim for about 1 ⅓ cups.

Whisk together the flour, baking soda, salt, and cinnamon in a large bowl until evenly combined.

Beat the softened butter, brown sugar, and granulated sugar in another bowl for about 2 minutes until light and fluffy.

Add the eggs one at a time, blending fully before adding the next; then stir in the vanilla and fold in the mashed bananas.

Slowly add the dry mixture to the wet mixture, folding gently until just combined.

Pour the batter into the prepared loaf pan, spreading it evenly, and bake for 45 to 60 minutes.

Allow the bread to cool in the pan for 5 minutes, then transfer it to a wire rack to cool completely.