Combine the flour, cocoa powder, baking powder and salt in a bowl.
In a separate bowl, beat the butter and brown sugar with an electric mixer until pale and fluffy. Add the egg and vanilla and mix well. Add the flour mixture in 3 additions, alternating with the buttermilk. Then add the red food colouring and mix until just combined.
Dollop tablespoon-sized pieces of batter onto baking sheets lined with parchment paper. Bake at 375F for 5-8 minutes. Cool them on the pan for 10 minutes, then transfer to a wire rack and cool completely.
To make the filling, beat the butter and cream cheese with an electric mixer until fluffy. Add the vanilla extract and combine. Add the confectioner’s sugar and beat until light and fluffy.
Use the red candy melts to draw the claws and legs onto a flat tray lined with parchment paper. Place in the freezer for the candy melts to set.
Place the filling into a piping bag fitted with a large, round tip and pipe onto half of the cakes. Place another cake on top, then stick the legs and claws into the filling. Use a small amount of filling to attach candy eyes. Enjoy!