Step 1

Pour the milk into a liquid measuring cup and add the tablespoon of vinegar to sour it. Stir, and let sit for a minimum of 15 minutes while you prepare the cake.

Step 2

Preheat the oven to 350°F. Grease a 9 X 9-inch cake pan and lightly dust with flour or spray with a floured baking spray.

Step 3

In a medium bowl, whisk together the flour, baking soda and salt.

Step 4

Cream the butter in a mixing bowl, slowly adding the sugar. Beat until light, about 2-3 minutes.

Step 5

Add the mashed banana, eggs, and vanilla to the butter / sugar, and mix well.

Step 6

Add the dry ingredients to the banana mixture and combine.

Step 7

Stir the milk, and with the mixer running on low, slowly pour it into the bowl and blend. Be sure to scrape down the sides of the bowl.

Step 8

Pour batter into the pan and bake for about 45 minutes, or until a toothpick inserted into the middle comes out clean.

Step 9

Cool the cake in the pan for about 5 minutes before turning out onto a rack. Then allow the cake to cool completely before frosting.

Step 10

Cream the butter and cream cheese in a mixing bowl until smooth and creamy. You may need to scrape down the sides of the bowl a few times

Step 11

Mix in the vanilla and the salt.

Step 12

Slowly add the powdered sugar and mix until thoroughly combined.