Step 1: Prepare the Baking Pan - Begin by greasing a 9x9-inch baking pan or lining it with parchment paper.
Step 2: Combine Peanut Butter and Corn Syrup - In a large mixing bowl, combine the heaping cup of creamy peanut butter and the light corn syrup. Mix until smooth.
Step 3: Add Sugars and Cocoa Powder - Add in the granulated sugar, light brown sugar, vanilla extract, and cocoa powder. Mix thoroughly until well incorporated.
Step 4: Fold in Rice Krispies and Butterfinger - Gently fold in the Rice Krispies and crushed Butterfinger until evenly distributed.
Step 5: Transfer to Baking Pan - Spoon the mixture into the prepared baking pan and press it down evenly.
Step 6: Chill to Set - Place the pan in the refrigerator for about 1 hour to firm up.
Step 7: Prepare the Chocolate Drizzle - Melt the semi-sweet chocolate chips and additional peanut butter in a microwave-safe bowl.
Step 8: Drizzle Over the Bars - Once the bars are firm, pour the melted chocolate over the top and spread it evenly.
Step 9: Chill Again - Return the bars to the refrigerator for another 30 minutes to allow the chocolate to set.
Step 10: Cut and Serve - Remove the bars from the pan and cut them into squares or rectangles.