In a large mixing bowl, mash 3 ripe bananas until smooth. Add 1 cup of sugar and ½ cup of melted unsalted butter, stirring until well combined. Beat in 2 room-temperature eggs and 1 teaspoon of vanilla extract. Gradually mix in 1 cup of all-purpose flour and 1 teaspoon of baking soda until just incorporated. Set aside.

In a separate bowl, beat 16 ounces of softened cream cheese with an electric mixer until creamy and smooth, about 2-3 minutes. Gradually add ½ cup of sugar, ½ cup of sour cream, and 2 room-temperature eggs, mixing until fully blended and free of lumps.

Grease a 9-inch springform pan and spoon half of the banana bread batter into the bottom. Carefully spoon half of the cheesecake batter on top, creating distinct layers. Repeat with the remaining batters.

Preheat your oven to 350°F (175°C). Place the springform pan inside a larger baking dish and fill it with hot water until it reaches halfway up the side. Bake for 75-90 minutes, or until set and lightly golden.

Allow the cheesecake to cool in the pan for at least 2 hours at room temperature. Once completely cooled, refrigerate for at least 4 hours. Prepare your cream cheese buttercream frosting and frost the cheesecake once chilled.