Preheat your oven to 350 degrees Fahrenheit.
Put 8 tbsp melted butter in a bowl with ¾ cup granulated sugar and ½ cup brown sugar. Use an electric hand mixer to combine.
Add 2 eggs and 1 tsp vanilla and mix to combine.
Put 8 oz (about 1 cup) chocolate chips in a microwave-safe bowl. Microwave in 20 second increments, mixing between each round. Microwave until fully melted, normally 3-4 rounds in total.
Add the melted chocolate into the butter/sugar combination. Use a rubber spatula to combine.
Sift in ¾ cup all-purpose flour, ¼ cup cocoa powder, and ½ tsp salt. Use your rubber spatula to mix until combined.
Grease an 8×8 glass pan with nonstick spray. Add the brownie batter to the pan.
Cook for about 45 minutes depending on desired doneness. Your brownies are done when a toothpick inserted in the middle comes out clean. I like my brownies slightly fudgy without hard edges, so I normally take them out when there's still a teeny amount of batter on the toothpick 😉
Allow the brownies to cool completely. When cooled, remove them from the pan.
Use a knife to cut the edges off of the brownies to make a perfect square. Cut the brownies into 12 identical pieces, a little bit longer then they are wide.
Put ½ cup frosting in a plastic bag and use scissors to cut a small corner off of the sandwich bag. Cut the tiniest little amount, because you want the frosting to come out as thin as possible.
Quickly and randomly pipe the frosting back and forth across the brownies. Add the candy eyes about ¼ of the way down from the brownie. Enjoy!