Preheat oven to 350℉ and line an 8x8 pan with parchment paper.
In a bowl, combine the wet ingredients for the banana coffee cake until well combined. Mix in the dry ingredients until you have a batter.
In a separate bowl, combine the crumb topping ingredients together.
Add half of your banana bread batter to the prepared pan, sprinkle half of the crumb topping over top. Add the rest of the banana bread batter on top and top it all off with the rest of the crumb topping.
Bake for 37-38 minutes and let cool completely before slicing and enjoying!