Ultimate recipe mashup!!! This simple chocolate chip banana sheet cake tastes like a chocolate chip cookie and banana bread combined. Great with plain, with coffee/milk or packed into kids lunch box
Preheat oven to 350 degrees F. Spray a 9 x 13 sheet pan ( if you don't have one then use a standard 9 x 13 baking pan) with non-stick cooking spray. Set aside.
Whisk together all dry ingredients in a small bowl and set aside.
Add butter and brown sugar into a large bowl, beat with a hand held electric beater for about 2 minutes, until light and fluffy.
Scrape sides, beat in egg.
Scrape sides, beat in mashed banana and vanilla extract, until smooth. (Don't worry if mixture looks slightly curdled at this point).
Add half the flour mixture, beat on low until barely smooth (do not over mix).
Add greek yogurt, beat on medium until combined.
Add remaining flour mixture, beat on low until just smooth (do not over mix).
Switch to a rubber spatula, stir in the chocolate chips and half chopped walnuts.
Transfer batter into the prepared pan, spread all over the pan, smooth top (try to do the best you can) and finally sprinkle remaining chopped walnuts on top.
Bake cake in the middle rack of the oven for 15-17 minutes, until it looks golden brown on top.
Place pan on a wire rack to cool completely.
Cut into squares and enjoy plain or with a tall glass of milk or hot cup of coffee.