Heat the oven to 350° Fahrenheit and grease a 9x13 inch pan with butter or cooking spray (or any pan size that you want! - 2 8-inch rounds, two square pans, cupcake pan, mini loaf pans...).

In a large bowl, use an electric mixer to cream together the butter and sugar until fluffy and lighter in color. Set aside. In a small bowl, mash 3.5 bananas together, then add to the butter and sugar mixture. Add in the eggs, sour cream, and vanilla - mix until well blended.

In a medium bowl, whisk together the flour, baking powder, and salt, then add into the wet ingredients and mix until just blended.

Pour batter into the greased pan and then slice the remaining 3.5 bananas and lay slices carefully on top of the cake (in patterns or side by side). Optional: stir together the extra melted butter and sugar and use a pastry brush to evenly distribute mixture over the top of the cake/bananas.

Bake for 40-50 minutes or until a knife inserted into the middle of the cake comes out clean. Let cool slightly before serving - enjoy!