Preheat oven to 325°F (170°C).

In a large bowl, whisk together granulated sugar, oil, banana, brown sugar, and peanut butter until well combined, about 1 minute. Add eggs and vanilla, and whisk until well combined. Whisk in buttermilk.

In a medium bowl, whisk together flour, baking powder, salt, and baking soda. Gradually whisk flour mixture into sugar mixture until just combined, stopping to scrape sides of bowl. (Do not overmix.)

Spray a 10-cup Bundt pan with baking spray with flour. Pour batter into prepared pan. Tap pan on a kitchen towel-lined surface 4 to 5 times to settle batter and release any air bubbles.

Bake until golden brown, a wooden pick inserted near center comes out clean, and an instant-read thermometer inserted near center registers 205°F (96°C), 50 to 55 minutes, covering with foil after 40 minutes of baking to prevent excess browning. Let cool in pan for 15 minutes. Invert cake onto a wire rack, and let cool completely.

When ready to serve, spoon Chocolate Glaze on top of cooled cake.