Preheat the oven to 350°F (175°C). Grease a 9x5-inch loaf pan.
In a bowl, whisk together flour, baking soda, and salt.
In another bowl, cream the butter and brown sugar until smooth.
Add eggs one at a time, beating well after each. Stir in mashed bananas.
Gradually add dry ingredients and stir until just combined.
Pour into the loaf pan and smooth the top.
Bake for 60–65 minutes, or until a toothpick inserted in the center comes out clean.
Let it cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.