Preheat oven to 350 degrees. Spray an 8 inch square baking pan or line with parchment paper.
In a measuring cup mix the milk and the vinegar and set aside.
Mix the butter and sugar together until light and fluffy.
Add eggs, Rodelle Vanilla and banana and mix until well combined.
In another bowl whisk together the flour, baking powder and baking soda.
Alternate adding the flour mixture and milk mixture and continue to stir until well combined.
Pour into the baking pan and cook for 20. minutes or until a toothpick inserted in the center comes out clean.
Remove from oven and cool well on a cooling rack before frosting. I suggest at least one hour.