Pre heat oven to 175 degrees Celsius and line 3 baking trays with baking paper.
Cream together butter and sugar with an electric mixer until smooth, then add vanilla extract and eggs. Continue mixing until well combined.
Add flour, cocoa powder, bi-carb soda and salt. Beat until a dough forms. Stir in choc chips for an even distribution through the mixture.
Roll a tablespoon full of dough into balls and spread 12 balls evenly onto each prepared baking tray. Bake for 8-10 minutes until they are set. Allow to cool for 2-4 minutes before inserting the candy eyes, extra choc chips and Smarties/M&Ms as desired. Cool completely on a wire rack before serving.
Happy Halloween. Enjoy!