Preheat the oven to 350 °F (177°C)and spray a muffin pan with nonstick cooking spray.
While your oven is preheating, in a bowl, use a fork to mash the bananas.
Add the vegetable oil, egg, and vanilla and stir to combine.
In a separate bowl, add the flour, sugar, brown sugar, baking soda, baking powder, cinnamon, and salt.
Whisk to mix.
Make a well in the dry ingredients and add the banana mixture to the well.
Stir until just mixed, making sure not to over-mix the batter. Fold in the nuts.
Spoon the batter into the muffin pan, filling each cup around 2/3 of the way full.
Prepare the streusel topping by stirring together the flour, oats, cinnamon, and brown sugar.
Add the butter and use a pastry blender or fork to mix the butter into the flour mixture until the mixture resembles coarse sand.
Sprinkle the topping over the top of the muffins.
Bake in the preheated oven for 25 minutes. Cool in the muffin pan once they are done. Set aside to cool completely.
Brew and prepare the coffee to your liking.
Prepare the fruit and mix in a bowl.
Butter the muffins and serve with fruit and coffee.