Cupcakes

Preheat the oven to 350°F (175°C). Prepare a standard 12-cup muffin tin by lining it with cupcake liners.

In a large mixing bowl, combine the flour, sugar, cocoa powder, baking powder, baking soda, and salt. Whisk together until evenly blended. Incorporate the buttermilk, oil, egg, and vanilla, whisking until a smooth batter forms. Carefully add the boiling water, whisking until fully integrated.

Distribute the batter evenly among the cupcake liners, filling each about two-thirds full. Bake for 18 to 20 minutes, or until a toothpick inserted into the center of a cupcake comes out clean. Allow the cupcakes to cool completely, approximately 1 hour.

Frosting & Assembly

In a large bowl or the bowl of a stand mixer equipped with a whisk attachment, combine the powdered sugar, butter, vanilla extract, and salt. Beat on medium-high speed until the frosting is smooth and bright white, about 2 to 3 minutes. Gradually add the neon green food coloring, blending until the desired shade is reached. Adjust the coloring as needed. Transfer the frosting to a piping bag fitted with a small round tip.

Pipe a small mound of frosting, about the size of a quarter, on top of each cupcake. Then, pipe two vertical lines down the middle of each cupcake. Next, pipe squiggly lines along both sides of the vertical lines to mimic brain-like folds.

Drizzle a small amount of red decorating gel over the top of each cupcake, allowing it to settle into the creases for a gory appearance. If not serving immediately, refrigerate the cupcakes to keep them fresh.