Preheat your oven to 325 degrees F. Spray two 8-inch round baking pan with nonstick cooking spray, line the bottoms with parchment paper, and spray again. Set aside.
In a medium bowl, whisk together the flour, baking powder, baking soda, salt and spices. Set aside.
In a stand mixer fitted with the paddle attachment, beat the butter, oil, and sugars on medium-high speed until pale and fluffy, about 5 minutes.
Lower the speed to medium and add the eggs, one at a time, mixing until each is fully incorporated before adding the next. Turn the mixer to medium-high and mix until smooth and fluffy, about 2 minutes. Add the vanilla.
With the mixer on low, add the dry ingredients alternating with the buttermilk mixture into the creamed mixture, starting and ending with the dry ingredients. Mix until just incorporated and remove bowl from stand mixer.
Stir in the bananas.
Evenly divide the batter between the two pans and bake for 38 to 43 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs on it.
Cool the cakes in the pans for about 15 minutes and then inverted onto a cooling rack until cooled completely.