Preheat Oven: Preheat to 350°F (175°C) and grease a 9x5-inch loaf pan.
Mash Bananas: In a bowl, mash bananas until mostly smooth.
Mix Wet Ingredients: Combine butter (or oil) and sugar, beat in eggs, and add mashed bananas and vanilla.
Add Dry Ingredients: In a separate bowl, whisk flour, baking soda, and salt. Fold into wet ingredients until just combined.
Bake: Pour into the loaf pan and bake for 55-60 minutes.
Cool: Let bread cool in the pan for 10 minutes, then transfer to a rack.
Prepare Frosting: Beat cream cheese and butter until smooth, add powdered sugar gradually, and mix in vanilla.
Frost and Serve: Spread frosting on the cooled banana bread, slice, and enjoy!