In a small saucepan melt the chocolate chips and butter over low heat. Stir until butter and chocolate are completely melted and combined.
In a medium bowl or stand mixer, beat together the sugar, eggs, vanilla, and *espresso powder. Stir in the melted chocolate and butter. Stir in the baking powder, salt, and flour until combined. Chill for 1-2 hours, or even overnight.
Preheat oven to 325 degrees. Line baking pans with parchment paper or lightly coat with non-stick cooking spray.
Add powdered sugar to a small bowl, but big enough to roll cookies for coating. Using a small scoop, form cookies into 2 inch balls. Roll in the powdered sugar so all sides are coated. Place on baking pan 2 inches apart, cookies will flatten and spread slightly.
Bake 10-11 minutes on the center rack. Cool cookies on a cooling rack. Store in an air tight container. Cookies can be frozen as well.
If you are unsure about the espresso flavor, start with just 1 tablespoon, taste the dough for desired coffee flavor, and go from there. I used about 2 tablespoons plus maybe a little more.