Step 1: Preheat your oven to 350°F (175°C) and line an 8×8 inch baking pan with parchment paper, leaving an overhang on two sides for easy removal.
Step 2: In a large mixing bowl, combine the melted butter and granulated sugar. Whisk vigorously by hand for about 2 minutes until the mixture is well combined and slightly pale.
Step 3: Add the eggs one at a time, whisking well after each addition. Stir in the vanilla extract.
Step 4: Sift the cocoa powder, flour, and salt directly into the wet ingredients. Use a rubber spatula to gently fold the dry ingredients in until just combined; do not over-mix.
Step 5: Pour the batter into the prepared baking pan and smooth the top with your spatula.
Step 6: Bake for 22-25 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs attached. Do not overbake!
Step 7: Remove from the oven and let the brownies cool for 5-10 minutes. While still warm, gently press the candy eyeballs into the top of the brownies in random clusters.
Step 8: Allow the brownies to cool completely in the pan before lifting them out and slicing into 16 squares.