Instructions

1. Preheat the oven to 180c and line two baking trays with baking paper.
2. Add the butter and sugar to a large bowl and beat with an electric whisk. Add the egg and continue to mix for another few seconds.
3. Add the flour, oats and cocoa powder and mix again until well combined.
4. Divide the mixture into 10 equal balls and then mould them into a cookie shape, placing 5 on each baking tray.
5. Bake in the oven for 15 minutes and leave the cookies on the tray to cool slightly.
6. Meanwhile place the marshmallows in a bowl and melt in the microwave. It will take between 20 and 60 seconds depending on the size of the marshmallows.
7. Use a spoon to drizzle the melted marshmallow over the cookies, creating a spider web design.
8. Leave to cool for another few minutes before serving.