For the cake:

1. Set oven rack to middle position and preheat to 350 degrees F. Grease a 10-12 cup bundt pan with non-stick spray and set aside.
2. In a large bowl, use a hand mixer to mash the bananas. Add the sour cream, vanilla, and cinnamon. Beat a few seconds to combine. Set aside.
3. In the bowl of a stand mixer, beat the butter, oil, and sugar until light and fluffy, 2-3 minutes.
4. Add the eggs, one at a time, and mix well after each.
5. Add the banana mixture and beat well to combine.
6. In a medium bowl combine flour, baking soda and powder, and salt. Add to mixer bowl and beat to combine. Add in cinnamon chips and stir by hand to combine.
7. Pour batter into prepared bundt pan. Smooth the top with a spatula and tamp on the counter several times to release any bubbles.
8. Bake at 350 degrees for 45-50 minutes, or until toothpick inserted near center comes out clean.
9. Remove from the oven and let rest for 10 minutes, then turn on to a cooling rack to cool completely.

For the icing:

1. With a hand mixer combine the cream cheese, powdered sugar, and vanilla until smooth.
2. Add milk a couple tablespoons at a time to get a drizzly consistency. Spoon over cooled cake.
3. Store cake, covered, at room temp for up to 3 days.