Preheat oven to 350F. Line a 9x5 loaf pan with parchment paper or lightly grease.
In a medium bowl, whisk espresso powder into warm melted butter. Mix in mashed banana, sugars, egg, yogurt, and vanilla until smooth.
In a separate medium bowl, combine flour, baking soda, and salt. Gently fold flour mixture into liquid until batter is just combined. Fold in zucchini and chocolate chips if using.
Scrape batter into prepared pan and smooth top. Bake bread at 350F 55-60 minutes until a toothpick inserted in center of bread comes out clean. Remove bread from oven and immediately brush top with brewed espresso.
Allow bread to cool completely in pan on a wire cooling rack. Once cooled, remove from pan and slice. Enjoy!