Preheat the oven to 325℉. Spray a 9x5x3" loaf pan with nonstick cooking spray.

Mix the smashed bananas, sugar, oil, eggs, and vanilla extract in a large bowl with a whisk. Add the flour, baking soda, baking powder, and salt into the bowl, and mix well to combine.

Pour the batter into the prepared loaf pan.

Bake until a wooden pick inserted in the center of the bread comes out clean, about 65-75 minutes, Let cool for 10 minutes, then tip the loaf from the pan and let cool completely before slicing.