Ask an adult to help preheat the oven to 180ºC/Gas Mark 4. Then, using some of the butter, grease a cupcake tray.
Stir the flour, baking powder and salt together in a bowl.
In another bowl, stir together the melted butter, sugar and vanilla extract and beat in the eggs one at a time with a spoon.
Gradually add the flour mixture and stir the batter until it is evenly moistened. Divide the batter in half in two separate bowls.
Stir the cocoa powder and chocolate chips into one bowl of batter. Then grab the second bowl of batter and stir in the pumpkin puree, cinnamon, and nutmeg. You can buy tinned pumpkin, or make your own puree by boiling the flesh of the pumpkin and mashing it.
Spread a spoonful of the chocolate batter into each of the cupcake holders. Then place a trick or treat into each cupcake! If you're using olives or cherries, make sure they don't have stones in them.
Now spoon the pumpkin mixture on top, to hide those tricks and treats!
Ask a grown-up to help you bake the cupcakes in a preheated oven. Bake them for about 30 minutes; the cupcakes should begin to pull away from the sides of the tin and a skewer inserted into the centre should come out clean.
Leave to cool in the tin, then add decorations like iced pumpkins and serve to your unsuspecting family and friends!