A cross between banana bread and cinnamon coffee cake dusted with a generous amount of powder sugar. Very moist banana cake base, and a crunchy cinnamon topping.
In a mixing bowl, whisk together the brown sugar, salt, cinnamon, and flour. Add the butter and with your hands, combine everything until it is well incorporated. You want it to have a shaggy look. Set aside. This can be made ahead o time and can be stored in an air tight container for up 5 days.
For the cake
Preheat your oven to 325 degrees. Spray a 9×13 metal pan on the bottom, line with parchment paper, and spray again this time also spraying the sides of the pan. If you need to use metal binder clips to hold down the sides, remember to use metal, not plastic. Set aside.
In a medium bowl, whisk the flour, baking powder, baking soda and salt. Set aside.
In another medium sized bowl, mash the bananas with a fork until they are completely mashed.
In a stand mixer fitted with the paddle attachment, beat the butter, oil, and sugar on medium-high speed until light and fluffy, about 5 minutes. With a rubber spatula, scrape down the sides and bottom of the bowl.
With the speed turned down to medium, add the eggs, one at a time, mixing until each egg is fully incorporated before adding the next (about 30 seconds for each addition). Add the vanilla and banana extract and mix on low.
With the mixer on low, add the dry ingredients, alternating with the buttermilk into the creamed butter mixture, starting and ending with the dry ingredients. I do it in the three parts.
Mix until just incorporated and remove bowl from stand mixer.
With a rubber spatula, fold in the mashed bananas until fully incorporated. Make sure to scrape down the bottom of the bowl.
Evenly distribute the banana batter to the prepped cake pan. With the back of a spoon, even out the batter to ensure it’s smooth for baking.
Evenly sprinkle the cinnamon topping on top of the banana cake batter.
Bake for 35-40 minutes. Check the cake by inserting a toothpick. It’s done when it comes out with just a few moist crumbs or no crumbs at all.
Let it come to room temperature before serving and. Dust with a little powder sugar on top, and serve.