Preheat oven to 350F. Spray a 9-in x 5-in x 3-in loaf pan with cooking spray.
In a large bowl, cream together sugar and shortening.
Then, beat in the eggs, vanilla, and mashed bananas. Scrape down the sides of the bowl.
In a separate bowl, combing flour, xanthan gum (if using), baking soda and salt.
Then slowly add in the flour mixture as you mix on low speed. Do not over mix.
Stir in the chocolate chips. Spoon the batter into the greased loaf pan.
Bake for 55-70 minutes, until the center is cooked through and the outside is browned. If your bread is getting brown too quickly, you can tent it with some foil for half of the baking time or bring it down to 325F half way through and just bake it for a little longer.
Mine worked perfectly, uncovered at 350F just under 60 minutes.
Makes 1 loaf of bread.