Preheat your oven to 375 degrees Fahrenheit. If you are making this into a cake, with shortening grease a casserole dish that measures 9 x 13. If you are making cupcakes, use liners in a muffin tin.
In a bowl, mash up the three bananas. Add the lemon juice and mix together well. Set this aside.
In another bowl, mix the cake flour, baking soda and salt. Set this aside.
In another bowl, cream together the butter and the sugar until it is light and fluffy. One at a time, beating in between each addition, add the eggs. Stir in banana extract.
Alternating between the bowl of dry ingredients (flour, salt, baking soda) and the buttermilk, beat into the creamy egg/sugar mixture. Just add a little buttermilk, mix, dry ingredients, mix, more buttermilk, mix, dry ingredients, mix... and so on until you have it all incorporated.
Using a spoon, stir in the mashed bananas.
Using a spatula, pour the batter into your prepared pan or into your cupcake liners.
Bake for 25-30 minutes for the cake, 15-25 for the cupcakes or until a toothpick inserted into the middle of a cupcake or the cake comes out clean. (obviously oven temps are going to vary).
Remove from the oven and allow to cool for 5 minutes. Move to a cooling rack and allow to cool the rest of the way.
For the record, these are great un-iced. But of course, you can ice these when cool. We used a light buttercream frosting and added a teaspoon of banana extract to give it a nice banana flavor. A true banana cupcake.
Garnish with sliced banana from the last banana. Enjoy!