The espresso powder will enhance the chocolate flavor.
Your brownies are done baking when the center is still moist, you should see moist crumbs not uncooked batter. Do not over bake them if you want gooey brownies.
Store your leftover brownies in an airtight container on the counter for up to 3 days, or in the fridge for up to 5 days.
Please keep in mind that nutritional information is a rough estimate and can vary greatly based on products used.