1. Make the cheesecake layer:
- Preheat your oven to 325°F (160°C). Line a 9-inch springform pan with parchment paper.
- In a mixing bowl, beat the cream cheese and sugar until smooth. Add the eggs and vanilla, mixing until just combined.
- Pour the cheesecake batter into the prepared pan and bake for 35–40 minutes, or until the center is set. Cool completely, then chill in the refrigerator for at least 2 hours.
2. Make the banana cake layers:
- Preheat your oven to 350°F (175°C). Grease and flour two 9-inch round cake pans.
- In a medium bowl, whisk together the flour, baking powder, baking soda, and salt.
- In a large bowl, beat the butter, oil, and sugar until light and fluffy. Add the eggs one at a time, then mix in the vanilla extract and mashed bananas.
- Gradually add the dry ingredients, alternating with the buttermilk, beginning and ending with the dry ingredients.
- Divide the batter evenly between the prepared pans and bake for 25–30 minutes, or until a toothpick inserted in the center comes out clean. Cool completely.
3. Make the banana pudding filling:
- In a bowl, whisk together the pudding mix and milk until thickened. Fold in the whipped cream gently to keep it light and fluffy. Chill until ready to use.
4. Make the cookie butter frosting:
- Beat the butter and cookie butter together until creamy. Gradually add the powdered sugar, beating well after each addition. Add heavy cream 1 tablespoon at a time until the frosting reaches your desired consistency.
5. Assemble the cake:
- Place one banana cake layer on a serving plate. Spread a layer of banana pudding filling on top.
- Place the chilled cheesecake layer on top of the filling. Spread another layer of banana pudding on top of the cheesecake.
- Top with the second banana cake layer. Spread the cookie butter frosting evenly over the top and sides of the cake.
6. Garnish and serve:
- Sprinkle crushed Biscoff cookies over the top and sides. Add sliced bananas, if desired. Chill the assembled cake for at least 1 hour before serving.