01 - Preheat oven to 350°F and line a 12-cup muffin tin with cupcake liners.
02 - In a large bowl, whisk together all-purpose flour, cocoa powder, sugar, baking soda, baking powder, and salt until evenly blended.
03 - In a separate bowl, whisk eggs, whole milk, melted butter, and vanilla extract until smooth.
04 - Pour wet mixture into dry ingredients and stir gently until just combined; avoid overmixing.
05 - Divide batter evenly among the prepared liners, filling each cup about two-thirds full.
06 - Bake for 18 to 20 minutes, or until a toothpick inserted in the center comes out clean. Allow cupcakes to cool completely on a wire rack.
07 - Using a small knife or cupcake corer, remove a small section from the center of each cooled cupcake. Fill each cavity with approximately 1 teaspoon seedless raspberry jam and replace the cut-off top.
08 - Beat room temperature butter until creamy with an electric mixer. Gradually incorporate sifted powdered sugar, then add milk and vanilla extract. Continue beating until light and fluffy. Add gel coloring to achieve desired shade.
09 - Transfer frosting to a piping bag fitted with a round tip. Pipe two squiggly lines on each cupcake to mimic the hemispheres of a brain.
10 - Drizzle or dot additional raspberry jam over the piped frosting for a blood-like effect, if desired.
11 - Arrange cupcakes on a platter and serve as a fun Halloween treat.