Step 1: Preheat Your Oven - Begin by preheating your oven to 350°F (175°C). This ensures the brownies bake evenly.
Step 2: Melt the Chocolate and Butter - In a microwave-safe bowl, combine the coarsely chopped unsweetened chocolate and butter. Microwave in 30-second intervals, stirring after each until melted and smooth. Be careful not to overheat.
Step 3: Mix the Sugar and Eggs - In a large mixing bowl, whisk together the melted chocolate mixture with the sugar until well combined. Add the eggs one at a time, whisking until fully incorporated. Finally, stir in the pure vanilla extract.
Step 4: Combine Dry Ingredients - In another bowl, whisk together the all-purpose flour and salt. Gradually add this to the chocolate mixture, stirring gently until just combined. Be cautious not to overmix.
Step 5: Fold in the Butterfinger Pieces - Gently fold in the chopped Butterfinger candy bars, ensuring they are evenly distributed throughout the brownie batter.
Step 6: Prepare Your Baking Pan - Line your 9x13-inch baking pan with parchment paper, leaving some overhang for easy removal later. Pour the brownie batter into the prepared pan and spread it evenly.
Step 7: Bake! - Bake in the preheated oven for 25-30 minutes or until a toothpick inserted into the center comes out with a few moist crumbs. Be careful not to overbake, as you want them to remain fudgy.
Step 8: Cool and Slice - Once baked, remove the brownies from the oven and let them cool in the pan on a wire rack. Once completely cooled, lift the brownies out using the parchment paper and cut them into squares.