Preheat oven to 350F. Lightly grease an oven-safe 9-inch cast iron skillet and set aside.
Place butter and chocolate in a large bowl and microwave 60-90 seconds, stirring at 30 second intervals until chocolate is melted. Allow to cool slightly.
Whisk espresso powder, sugars, eggs, vanilla, flour, cocoa powder, and salt into cooled chocolate mixture until smooth. Fold chocolate chips into batter until combined. Pour batter into prepared pan and smooth top.
Bake brownies at 350F 20-25 minutes until top is set and crackly. Allow brownies to cool completely on a wire cooling rack before cutting into wedges and serving with vanilla ice cream. Enjoy!
Notes
Storing InstructionsStore brownies in an airtight container at room temperature up to 4 days.