Preheat oven to 325°F/165°C.

Grease a 9 x 13-inch (23 x 33 cm) glass baking dish and line with parchment paper.

Using a double boiler, or heatproof bowl over saucepan of water, heat butter and chocolate over low heat until melted, stirring gently. Turn of heat when melted, but keep bowl over saucepan to keep mixture warm.

Mix the sugar into the butter and chocolate.

In a separate mixing bowl, lightly beat the eggs and vanilla together. Add the eggs to the chocolate mixture and stir until fully mixed. Add the flour and baking powder to the chocolate mixture and mix until you can no longer see any flour. Pour the batter into the prepared pan and spread evenly with a spatula.

Bake for 1 hour or until a toothpick comes out clean when inserted.

Allow to cool completely in the pan, then remove using parchment paper to lift out.

In a bowl, mix the confectioners sugar with the milk until smooth.

Add black food coloring (I used a toothpick to add a very small amount), in small amounts until a stone grey color is achieved.

Smooth over the cookies and allow to dry on a cooling rack.

Pour the melted white chocolate into the skeleton mold and refrigerate until hardened then remove from mold.

Place brownie on a cutting board.

Cut 3 graves measuring 2 1/4 x 5 inch (6 x 13 cm) in the brownie evenly spaced.

Using a fork, rake out the brownie so it crumbles like soil, put into a bowl. Mound the 'soil' back into the 'graves'. Arrange skeleton parts in and around the 'graves'.

Using a sharp knife, cut a small area of brownie out at the head of the graves and insert cookies into the brownie.

In a mixing bowl, add the frosting and a few drops of green food coloring to achieve the desired color.

Add to a piping bag using piping tip 233 and pipe 'grass' around the graves.