01 - Preheat oven to 350°F. Line a 12-cup muffin tin with cupcake liners.
02 - In a large bowl, cream butter and sugar until light and fluffy. Beat in eggs one at a time, then vanilla. In a separate bowl, whisk flour, baking powder, and salt. Add half of the dry mixture to the wet, then add milk, then mix in remaining dry ingredients until just combined.
03 - Divide batter evenly among liners, filling each 2/3 full. Bake for 18-20 minutes or until a toothpick inserted comes out clean. Cool completely on a wire rack.
04 - Beat butter until creamy. Add powdered sugar and cocoa powder, mixing slowly. Add vanilla and milk, beating until smooth and spreadable.
05 - Arrange cooled cupcakes close together on a serving tray in a rectangle or mound shape. Generously spread chocolate frosting over all cupcakes, creating a smooth surface.
06 - Crush chocolate sandwich cookies and sprinkle over frosting for dirt. Write RIP and spooky messages on rectangular cookies with gel icing pens to make tombstones. Press into cupcakes. Decorate with gummy worms, candy pumpkins, or spooky candy.
07 - Chill briefly before serving to set decorations.