Blitz all of the biscuits to a fine crumb, and mix in the melted unsalted butter (I used a food processor).
Press this into the sides and base of a 23cm Pie/Flan tin (mine was 3cm deep). It might be easier to use your hands and fingers for this! Make sure that the side parts are thick enough to hold the filling once removed from the tin.
Refrigerate for now.
Put all of your finely chopped milk and dark chocolate into a large bowl with the cubed unsalted butter.
In a small pan, heat the double cream until just before boiling point. You will see it starting to bubble at the sides.
Once hot, pour over the chocolate and butter and whisk until smooth! If the chocolate hasn’t fully melted by this point, heat it in the microwave in 10 second bursts, stiring every time - this will be quite runny.
Once the mixture is smooth, pour onto the biscuit base.
Tip on all of your mini marshmallows, so the top of the tart is covered in marshmallows.
Leave to set in the tin for 3-4 hours, or overnight.
Whilst still in the tin, CAREFULLY blowtorch the top of the marshmallows so they get the 's'mores' style, or you can very quickly and carefully broil under the grill on a lower setting - it really won't need long as the marshmallows brown quite quickly, and you don't want to completely melt the chocolate layer.
Refrigerate again to cool it down once toasted.
Carefully remove from the tin, and transfer to your favourite serving plate -serve with a dollop of cream, or on its own, or with even more marshmallows – yum!
For this dessert I used the mini marshmallows that you can buy in the bakery isle of a supermarket - I find that mini ones are easier than larger ones as they need less grilling/torching time.
This dessert will make a very indulgent chocolate tart without the marshmallows if you would rather not use them, but will loose the s'mores theme!
You can easily double up the recipe to make a bigger & deeper pie – add another half of the base recipe (I.e. use 450g biscuits, and 200g butter) and double the filling recipe! Use a 25cmx5cm deep tart tin!
This dessert will last in the fridge for 3 days, covered.