1. Preheat oven to 185 degrees.
2. Beat together the brown sugar, caster sugar, and melted butter, until lighter in colour.
3. Add the eggs and mix until smooth.
4. Add the dry ingredients and mix until combined.
5. Fold in all the monster mash pieces.
6. Form your cookie dough balls and place in the freezer for 30 minutes.
7. Bake for 12 minutes, allow to cool and add melted chocolate drizzle, if desired.