• Heat oven to 325°. Line 3 large baking sheets with parchment paper.

  • Place chopped chocolate in a small glass bowl. Microwave 1 minute; stir until smooth and set aside to cool slightly.

  • In a medium bowl, whisk flour, cocoa powder, baking soda and salt.

  • In large bowl of a stand mixer, beat butter until smooth. Add brown sugar and beat on medium-high speed 5 minutes, occasionally scraping down sides of bowl. Add egg and beat 3 minutes more. Stir in vanilla and melted chocolate. On low speed, beat in flour mixture. Fold in chocolate chunks or chips.

  • Place granulated sugar in a small bowl. Scoop up 2 slightly heaping tbsp of dough and roll it into a ball between your hands. Roll ball in sugar to coat. Place cookie on prepared baking sheet and flatten slightly with your hand. Repeat with all the remaining dough and granulated sugar.

  • Bake cookies in batches at 325° for 14 minutes per batch or until cookies crack. Cool on pan for a few minutes, then carefully transfer to a wire rack to cool completely.