Preheat your oven to 350°F (175°C). Line one 8x4-inch loaf pan with parchment paper, or grease them generously with butter or baking spray.
In a medium bowl, use a fork to mash the bananas until smooth with some tiny chunks left for texture. Set aside.
In a large mixing bowl, beat the room-temperature unsalted butter and granulated sugar together using a mixer until light and fluffy.
Add the eggs one at a time, mixing well after each addition until fully incorporated.
Gradually stir in the all-purpose flour, baking soda, and salt. Mix until just combined—do not overmix to keep the bread tender.
Gently fold in the mashed bananas and vanilla extract using a spatula. (If using chocolate chips or nuts, fold them in now!).
Pour the batter into your prepared loaf pan. Bake for 35 to 40 minutes, or until golden brown and a toothpick inserted into the center comes out clean.
Allow the bread to cool in the pans for 5–10 minutes, then transfer to a wire rack to cool completely before slicing.