Preheat the oven to 350°F. Line a 9 x 13 baking dish with parchment paper. In a medium pot, melt the butter over low heat.

Add the cocoa powder and sugar, and mix to combine. Add the eggs one at a time, mixing well after each addition.

Stir in the vanilla. Add the flour, salt, and baking soda, and mix until just combined. Fold in the chocolate chips.

Pour the batter into the prepared pan, and sprinkle with the chocolate jimmies. Bake for 40-45 minutes, until a toothpick inserted in the center comes out clean.

Let cool for 10-15 minutes, then place the ghost candies on top. Let cool completely before slicing and serving.