A fudgy brownie base topped with playful marshmallow ghosts coated in melted white chocolate and decorated with black gel eyes for a fun Halloween treat.
Preheat oven to 350°F. Coat an 8-inch square pan with cooking spray and line bottom with foil.
In a large bowl, whisk together brownie mix, eggs, vegetable oil, and water until smooth.
Pour batter into prepared pan and bake until a toothpick inserted 4 inches from edge comes out with moist crumbs, about 25–30 minutes.
Let brownies cool completely in pan on a wire rack, about 30 minutes.
Ghost Topping
Transfer brownies to a cutting board and slice into 12 squares. Slice each marshmallow in half crosswise and press two halves into each brownie square, flat side first.
In a microwave-safe bowl, combine white chocolate chips and coconut oil. Microwave at 50% power in 30-second bursts, stirring until smooth.
Spoon melted chocolate over each marshmallow ghost and let excess drip off onto waxed paper. Refrigerate 10 minutes to set.
Finish by piping eyes and mouths with black decorating gel.
Notes
Testing Note 1: After one batch, I chilled the pan before cutting to firm up the edges and prevent crumbling.Testing Note 2: Melting white chocolate at 50% microwave power in short bursts kept it silky and avoided scorching.Testing Note 3: Store brownies flat in a single layer to keep the marshmallow ghosts from sticking and preserve their shape.