Preheat oven to 350°F and grease an 8″ x 4″ loaf pan.
In a medium bowl, whisk together flour, baking powder, baking soda, cream of tartar and salt, set aside.
In the bowl of an electric stand mixer, beat together canola oil and sugar. Add egg and continue mixing. Add zucchini and mix on medium until well blended.
Starting and ending with the flour, alternate adding the flour mixture and the mashed banana, a little at a time, while the mixer runs on low.
Fold in the chocolate chips and pour batter into prepared loaf pan.
Bake 50 to 55 minutes, tenting with foil for the last 15 minutes to avoid too much browning. Allow bread to cool before slicing, serve warm with a little butter.
