Preheat oven to 350°F (175°C).

In a large bowl, combine mashed bananas and sugar.

Mix in the beaten egg and oil until well combined.

In a separate bowl, whisk together flour, soda, salt, and baking powder.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Do not overmix.

Pour batter into a greased loaf pan.

Bake for 60 minutes, or until a wooden skewer inserted into the center comes out clean.

Let cool in the pan for 10 minutes before transferring to a wire rack to cool completely before slicing and serving.