For the Cream Cheese Frosting
For the Cake
Preheat oven to 350˚F. Lightly grease a 9x13 glass baking dish with cooking spray; set aside.
In a large mixing bowl beat butter on high until creamy; about 30 seconds.
Add sugar, baking powder, baking soda, and salt; beat until combined. Add egg, mashed bananas, sour cream and vanilla; beat until incorporated.
Mix in the flour; continue to mix until combined.
Stir in the pecans.
Transfer the batter to the baking dish and, using an offset spatula, spread the batter evenly.
Bake for 30 to 40 minutes, or until a toothpick inserted in the center comes out clean.
For the Cream Cheese Frosting
In your mixer's bowl, combine the cream cheese, butter, and vanilla; mix until fluffy and completely combined.
Slowly add powdered sugar, about 1/3 cup at a time; continue to mix until smooth and thoroughly incorporated.
Remove the cake from the oven and let it cool completely on a wire rack.
Frost the cooled cake with the Cream Cheese Frosting.
Cut and Serve.