Preheat oven to 350°F (180°C).

In the bowl of a stand mixer fitted with the paddle attachment, combine banana, buttermilk, brown sugar, 1/2 cup (113 grams) melted butter, 1/4 cup (50 grams) granulated sugar, oil, 3 eggs (150 grams), bourbon, and 1 teaspoon (6 grams) vanilla bean paste; beat at medium-low speed until well combined, about 2 minutes, stopping to scrape sides of bowl.

In a large bowl, whisk together 3 cups (375 grams) flour, baking powder, baking soda, salt, cinnamon, and nutmeg. With mixer on low speed, gradually add flour mixture to banana mixture, beating until combined and stopping to scrape sides of bowl. Transfer batter to a large bowl.

Clean bowl of stand mixer and paddle attachment. Using the paddle attachment, beat cream cheese, remaining 3 tablespoons (36 grams) granulated sugar, and remaining 2 teaspoons (6 grams) flour at medium speed until smooth and well combined, 1 to 2 minutes, stopping to scrape sides of bowl. Add remaining 1 egg (50 grams) and remaining 1/2 teaspoon (3 grams) vanilla bean paste; beat at medium speed until smooth and well combined, about 2 minutes, stopping to scrape sides of bowl.

Spray a 10-cup Bundt pan with baking spray with flour. Spoon 4 cups batter (about 956 grams) into prepared pan; forcefully tap pan on counter several times to release as many air bubbles as possible. Spoon a ring of cream cheese mixture in center of batter in pan, leaving a 1/4-inch border around inside and outer edges of pan. (Cream cheese mixture will have the consistency of cheesecake filling, so you will be able to almost drizzle, rather than dollop, the mixture; it is fine if cream cheese mixture touches sides of pan in places.) Using a butter knife, gently swirl cream cheese mixture into batter using a folding motion. Spoon remaining batter on top, covering cream cheese mixture. Do not tap pan. (Pan will be quite full, but batter will not overflow during baking.)

Bake for 45 minutes. Cover with foil, and bake until a wooden pick inserted near center comes out clean and an instant-read thermometer registers at least 200°F (93°C), 15 to 20 minutes more. (It’s OK if some cream cheese mixture peeks through surface of cake.) Let cool in pan for 20 minutes. Invert cake onto a wire rack placed over a parchment-lined rimmed baking sheet, and let cool completely.

Brush cooled cake with remaining 2 tablespoons (28 grams) melted butter; cover with sanding sugar, pressing gently to help adhere. Serve immediately.