• Preheat the oven to 350F/180C.

for the crust

• Mix together the Graham cracker crumbs and melted butter until all the liquid has been absorbed. Press into an 8x8" tin which has been lined with parchment paper.

for the brownies

• Melt the butter and chocolate together in the microwave.
• Pour in the sugar and vanilla and beat until fluffy.
• Add in the eggs one at a time, mixing well after each.
• Fold in the flour and pour on top of the Graham cracker crust. Bake for 30-35 minutes.

for the marshmallow topping

• Cover the top in marshmallows and broil for 1-2 minutes, or until the marshmallows have just turned golden. Don't let them burn! Alternatively use a kitchen blow torch to toast the marshmallows.
• Leave for 2-3 hours to cool completely before slicing and serving.