Step 1: Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
Step 2: In a medium saucepan over low heat, combine the chopped bittersweet chocolate and unsalted butter. Stir until melted and smooth. Remove from heat and let cool slightly.
Step 3: In a large mixing bowl, whisk together the granulated sugar and eggs until light and frothy, about 2-3 minutes.
Step 4: Stir in the instant coffee and vanilla extract into the egg mixture, mixing until well combined.
Step 5: Slowly pour the melted chocolate and butter mixture into the egg mixture, stirring continuously until well blended.
Step 6: In a separate bowl, whisk together the all-purpose flour, cocoa powder, baking powder, and salt. Gradually add this dry mixture into the chocolate-egg mixture, stirring until just combined.
Step 7: Gently fold in the toffee bits, ensuring they are evenly distributed throughout the dough.
Step 8: Using a cookie scoop or tablespoon, drop rounded balls of dough onto the prepared baking sheet, leaving about 2 inches between each cookie.
Step 9: Bake for 10-12 minutes, or until the edges look set but the centers are still soft.
Step 10: Let the cookies cool on the baking sheet for 5 minutes before transferring them to a cooling rack to cool completely.
