1. Preheat your oven to 180°c fan or 200°c for a conventional oven.
2. Grease and line a 30x15cm tray with greaseproof paper.
3. Melt the chocolate and butter in a bowl over a pan of simmering water, being careful not to let the bottom of the bowl touch the water.
4. In a mixing bowl, whisk the sugar, vanilla and eggs together until light and fluffy.
5. Add the chocolate and butter mix into the egg mix and fold in.
6. Fold in the flour and cocoa powder, then the chocolate chips.
7. Pour the mixture into the baking tray and spread out evenly.
8. Push the marshmallows in to the mix.
9. Bake in the Leisure range cooker for 20-22 minutes. There should be no wobble but it’ll still look a little undercooked, which is perfect.
10. Before it cools, break each biscuit into roughly three pieces. Add these evenly into the mix, with half sticking out.
Recipe courtesy of Leisure / Dan Doherty