To Make the Cake

1. Preheat oven to 350 degrees F.  Grease and flour a jelly roll pan – we used this 9 ½ x 14-inch pan from USA Pan but a 10 ½ x 15-inch quarter sheet pan will also work.
2. In a large bowl with a mixer, beat together butter and sugar until the mixture resembles crumbs. Add eggs and vanilla and mix again.
3. In a separate bowl, whisk together flour, baking soda, and salt.
4. Add the dry flour mixture to the butter mixture, scraping sides and bottom of the bowl to mix completely. (Do not over mix.)
5. Add mashed bananas and buttermilk to the batter and mix until completely blended on low speed. Fold in chocolate chips with a rubber scraper or wooden spoon.
6. Pour the batter into the prepared jelly roll pan and bake for 25 to 30 minutes (the smaller 9 ½ x 14-inch pan we used took about 32 minutes to bake) turning halfway through baking. You’ll know the cake is done when the corners start to pull back from the sides of the pan and the top of the cake springs back when pressed gently in the center.
7. Remove cake from the oven and cool completely on a rack before frosting.

To Make the Frosting

1. Once the cake has cooled, prepare the frosting.
2. In the bowl of a stand mixer fitted with the paddle attachment, place the cream cheese, butter, and vanilla. Mix on medium speed just until combined, but do not whip.
3. Slowly add the confectioner’s sugar and mix until smooth.
4. With an offset spatula, evenly spread the prepared Cream Cheese frosting over the cooled Banana Chocolate Chip Sheet Cake.  Sprinkle the top with the mini chocolate chips.