Preheat the oven to 375F. Combine the dry ingredients in a medium sized bowl: the flour, cinnamon, baking powder, salt, baking soda. Stir until combined then set aside.

In a large bowl, add the olive oil, greek yogurt, brown sugar, eggs, and vanilla. Peel and mash the bananas, then add them to the bowl. Whisk until well combined. Add the dry ingredients and mix until just combined, until there are no flour streaks remaining. Set aside.

To make the streusel, add the brown sugar, rolled oats, flour, cinnamon, and salt to a bowl and mix to combine. Add the cold, cubed butter to the bowl. Use your fingers to break up each piece of butter, pressing it into the flour. The streusel should stick together if you squeeze it in your fist, but should crumble when you run it through your fingers.

Line a muffin tin with baking cups. Scoop about 1/3 cup of batter into each one and top with a handful of streusel. Transfer to the oven and bake for 25-30 minutes, until an inserted toothpick comes out clean. Enjoy!