1 box (18.4 oz) fudge brownie mix (plus eggs, oil, and water as required by the box)
1 cup vanilla frosting
Neon green food coloring
1/2 cup candy eyeballs
1/4 cup Halloween-themed sprinkles (bones, stars, or bats)
16 pretzel sticks (to act as stirring spoons)
Green pearl candies or nonpareils (for bubbles)
Instructions
Preheat your oven to 350°F (175°C). Grease an 8×8 inch or 9×9 inch square baking pan with non-stick spray or line it with parchment paper, leaving an overhang on the sides for easy removal.
In a large bowl, combine the brownie mix with the water, oil, and eggs according to the package instructions. Stir until just combined, being careful not to overmix, as this ensures a fudgy texture.
Spread the batter evenly into the prepared pan. Bake for 25 to 30 minutes, or until a toothpick inserted into the center comes out with just a few moist crumbs. Allow the brownies to cool completely in the pan.
Once cooled, lift the brownies out of the pan and cut them into 16 even squares. In a small bowl, mix the vanilla frosting with a few drops of neon green food coloring until you achieve a bright, “toxic” green hue.
Spread a thick circle of green frosting in the center of each brownie square, leaving a small border to represent the rim of the cauldron. While the frosting is wet, press in candy eyeballs, sprinkles, and green pearl candies to look like a bubbling potion. Finish by sticking a pretzel stick into the side of the frosting at an angle to serve as the stirring spoon.