10tablespoons(1 1/4 sticks) unsalted butterat room temperature
1 1/2cupspacked light brown sugar
1cupsemisweet chocolate chips
1cupwhite chocolate chips
In a medium bowl, whisk together flour, cocoa powder, baking powder, and salt.
Melt chocolate chips in a glass bowl in the microwave, stirring after the first minute and then every 30 seconds after that until smooth and melted. (Alternatively, you may melt chocolate in a double boiler/heatproof bowl set over a pan of simmering water.) Set aside to cool.
In a small bowl, beat eggs with vanilla. Sprinkle coffee or espresso powder over the top and let sit until dissolved/absorbed by eggs. Mix in.
In a large bowl, use an electric mixer to beat butter until smooth and blend in both sugars until well mixed. With mixer on low, stir in egg mixture. Blend in melted chocolate until well incorporated, scraping bowl and mixing again before proceeding. Slowly stir in dry ingredients, mixing until just combined. Fold in chocolate chips. Cover bowl with plastic wrap and set aside at room temperature for 30 minutes to allow consistency of the cookie dough to become fudge-like.
Preheat oven to 350°F. Line cookie sheets with parchment paper. For each cookie, scoop approximately 3 tablespoons of dough into a mound (I use a size 20 cookie scoop and level off the dough). Space mounds of dough 1 1/2 inches apart. Bake for 10 minutes, or until edges of cookies are just set and centers are still soft. Allow cookies to cool on pans for 10 minutes before transferring to a wire rack.
Dutch-processed cocoa powder gives these cookies a darker color and a deeper chocolate flavor than regular cocoa powder would.
The instant coffee or espresso powder in these cookies don't make them taste like coffee. They just enhance the flavor of the chocolate even more.