Finally! You don't need to wait for barbecue weather to get your hands on some tasty s'mores; now available in tart form!
Combine the dry ingredients, sieving the flour, baking powder, bicarbonate of soda and bran.
Add the butter to the mixture and rub through with your fingertips until the mixture looks like breadcrumbs.
Begin to add the milk, a tbsp at a time, stirring in well until the dough begins to come together in a soft ball.
Wrap the dough in greaseproof paper or cling film and refrigerate for at least 30 minutes.
Take small pieces of the dough and carefully press into either one 25 cm, or four 8 cm, tart cases. Try and make the tart shell as thin as possible, while making sure there are no gaps or cracks.
Refrigerate the case(s) for 30 minutes and preheat the oven to 190oC.
Bake for around 12 minutes, or until lightly browned. Cool on a wire rack, and then the fridge to allow the biscuit to harden.
Preheat the oven to 120oC.
Combine the milk and cream in a saucepan and bring to the boil. Remove from the heat.
Add the chocolate and let the mixture stand for 5 minutes. Whisk until smooth.
In a bowl, whisk the egg with the egg yolks, before whisking in around a quarter of the chocolate cream.
Pour this chocolate custard back into the chocolate cream in the saucepan, whisking thoroughly until well combined.
Add the custard into the cooled tart shell(s) and bake for around 30 minutes for a large tart, and 20 minutes for smaller ones. The custard is done when it is set around the edges but slightly wobbly in the centre. Cool on a wire rack before refrigerating for 2 hours.
Take the marshmallow and distribute liberally across the top of the tart(s).
Scorch the marshmallow with a blowtorch or under a grill (broiler) until golden and dark brown.