Preheat the oven to 350°F. Lightly grease a 9-inch by 5-inch loaf pan with butter or vegetable oil.
Prepare the streusel by combining the flour, brown sugar, cinnamon, and softened butter in a mixing bowl. Use a large spoon, fork, or your hands to crumble the mixture into tiny pieces. Set aside.
In a large mixing bowl, whisk together the flour, baking soda, baking powder, salt, cinnamon, and espresso powder. Set aside.
In a separate mixing bowl, mash the peeled bananas with a fork. Add the vegetable oil, granulated sugar, brown sugar, egg, and vanilla extract. Whisk to combine.
Add the dry ingredients into the wet ingredients, and gently mix until there is no dry flour visible.
Pour the batter into the greased loaf pan. Sprinkle the streusel on top.
Bake for 50 to 60 minutes, until a wooden skewer or knife inserted into the center of the bread comes out without any wet batter stuck to it. Allow the bread to cool in the pan for 15 minutes, then transfer it to a cooling rack. Let it cool for at least another 10 minutes, then slice & enjoy!!