1. Preheat the oven to 350°F (175°C). Grease a loaf pan.

2. In a large bowl, cream together the butter and sugar until light and fluffy.

3. Add the eggs one at a time, beating well after each addition. Stir in the mashed bananas and vanilla extract.

4. In a separate bowl, whisk together the flour, baking soda, and salt. Gradually add the dry ingredients to the banana mixture, stirring just until combined.

5. Pour the batter into the prepared loaf pan. Bake for 60-70 minutes or until a toothpick inserted into the center comes out clean.

6. Remove from the oven and let cool in the pan for 10 minutes. Transfer to a wire rack to cool completely before slicing.