Preheat your oven to 350°F (175°C). Grease and flour two 9-inch round cake pans, or line them with parchment paper for easy removal.

1. In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.
2. In a large bowl, beat the softened butter and granulated sugar together until light and fluffy, about 3-4 minutes.
3. Add the eggs one at a time, beating well after each addition. Then, stir in the vanilla extract.
4. In a separate bowl, mash the bananas until smooth. Add the mashed bananas, sour cream, and buttermilk to the butter mixture, mixing until combined.
5. Gradually add the dry ingredients to the wet ingredients, mixing until just incorporated. Be careful not to overmix.
6. Divide the batter evenly between the prepared cake pans and smooth the tops.
7. Bake for 25-30 minutes, or until a toothpick inserted into the center of the cakes comes out clean.
8. Let the cakes cool in the pans for 10 minutes before transferring them to wire racks to cool completely.
9. For the frosting: In a small saucepan, cook the chopped strawberries over medium heat for about 5-7 minutes, or until they release their juices and become soft. Allow the mixture to cool to room temperature.
10. In a large mixing bowl, beat together the softened cream cheese and butter until smooth and creamy.
11. Add the mashed bananas, vanilla extract, and the cooled strawberry mixture, mixing until everything is well combined.
12. Gradually add the powdered sugar, one cup at a time, and beat until the frosting is smooth and fluffy.
13. Once the cakes have cooled completely, spread a layer of frosting on the top of one cake layer. Place the second cake layer on top and frost the entire cake with the strawberry-banana frosting.
14. Decorate the top with additional fresh strawberry slices and banana slices, if desired.
15. Slice, serve, and enjoy!