Preheat oven. Preheat oven to 350°F and grease a large loaf pan or 3 mini loaf pans.
Cream butter and sugar. In a large bowl, use a hand mixer to cream the softened butter and sugar until smooth and creamy.
Add dry ingredients. Add the flour, salt, baking soda, and baking powder. Mix until just combined.
Finish batter. Add the eggs, mashed bananas, and bourbon. Mix until just combined.
Fill pan. Pour the batter into the prepared loaf pan or divide evenly between 3 mini loaf pans.
Bake. Bake for about 35 minutes for mini loaves or 55–60 minutes for one large loaf. The bread is done when a toothpick inserted into the center comes out clean or with a few moist crumbs.
Cool. Let cool in the pan for about 10 minutes, then transfer to a wire rack to finish cooling before slicing and serving.
Notes
Bananas: Use very ripe or overripe bananas for the best sweetness and banana flavor.
Bourbon: Whiskey or rum can be substituted using the same amount.
Add-ins: Fold in chopped walnuts, pecans, chocolate chips, raisins, or cinnamon chips if desired.
Pan Sizes: Bake at 350°F for about 25 minutes for muffins, 35 minutes for mini loaves, or 55-60 minutes for one large loaf.
Doneness: Baking times can vary by pan and oven, so use the toothpick test to check the center.