Start by gathering all your ingredients on the counter. It makes the process smoother and faster.
In a medium saucepan over medium heat, add the salted butter and allow it to melt completely. Once melted, stir in the cocoa powder, granulated sugar, and milk. Mix well until everything is combined and smooth.
Increase the heat slightly and bring the mixture to a rolling boil. Allow it to boil for exactly one minute.
After one minute, remove the saucepan from the heat. Stir in the peanut butter and vanilla extract, mixing until the peanut butter is fully melted and incorporated.
Add the quick-cooking oats and coarsely chopped Butterfingers to the mixture. Stir until everything is well-combined and the oats are evenly coated.
Using a spoon or cookie scoop, drop spoonfuls of the mixture onto a baking sheet lined with parchment paper.
Before the mixture sets, sprinkle a few extra Butterfinger pieces on top of each cookie for added crunch and visual appeal.
Allow the cookies to cool at room temperature for about 30 minutes, or until they are firm and set.
