Preheat oven to 350℉ / 180℃
Combine flour, cocoa powder, sugar, cornstarch, baking powder and baking soda in the bowl of a stand mixer. If mixing by hand or with a hand mixer, combine ingredients in a large mixing bowl.
⅓ cup Cocoa Powder, 1 cups All Purpose Flour, 1 cups Granulated Sugar, 1 Tablespoon Corn Starch, 1 teaspoons Baking Powder, ¼ teaspoon Baking Soda
Add oil and eggs. Mix until combined.
⅓ Cup Vegetable or Canola Oil, 2 Large Eggs
Slowly pour brewed coffee into bowl while continuing to mix, scraping the bowl occasionally (note - water may be substituted for the coffee). The batter should be smooth.
⅔ Cup Brewed Coffee (cooled)
Pour cake batter into pan over top of bananas and caramel layer.
Bake for 30 - 35 minutes, or until cake is fully risen and a toothpick inserted in the center of the cake comes out clean (to check internal temperature: insert a instant read thermometer into center of cake. Cake is finished baking if temperature is 180℉ / 83℃).