1 stick (1/2 cup) unsalted butter
3/4 cup plus 2 tablespoons light brown sugar, packed
2 large eggs
1 teaspoon vanilla extract
1-2/3 cups all purpose flour, spooned into measuring cup and leveled off with a knife
1/3 cup Dutch-process cocoa powder (ok to substitute natural cocoa powder)
3/4 teaspoon salt
1/2 teaspoon baking powder
1/2 teaspoon baking soda
1/2 teaspoon espresso powder or instant coffee (optional)
2 cups shredded zucchini (from 1-2 zucchini), gently packed
1 cup semi-sweet chocolate chips