Heat your BBQ or the OONI and once it has come up to cooking heat, place the Sandwich Iron inside to heat up.
In the meantime roll your cookie dough out into a single sheet. I aimed for a thickness of around 5mm. Once rolled slice in half.
Remove the Sandwich Iron from the OONI or BBQ and open it up. Carefully lay each half of the cookie dough onto each half of the Sandwich Iron. Gently press down to shape the dough to the Sandwich Iron. Be careful as it will be hot!
Next, sprinkle a handful of mini-marshmallows on the bottom section then close up the Sandwich Iron. There will be some excess dough so trim this off with a knife.
Place in the OONI or BBQ and cook for 6 minutes on each side. Remove and check that the dough is properly cooked. If not put it back for a few more minutes. When it is ready, remove it from the OONI and open up the Sandwich Iron.
Allow it just to sit for a couple of minutes, then remove and serve with ice cream and a drizzle of chocolate sauce.