1. Preheat oven to 170°C fan. Grease 4 x 10cm tartlet tins.

2. To make the sweet pastry: If making pastry by hand, sieve the flour and icing sugar together into a bowl. With the tips of your fingers, rub in the diced butter until all the butter is worked in and it resembles fine breadcrumbs. Use a knife to work in the egg yolk and water then bring together to form a dough, wrap in clingfilm and refrigerate for 20 minutes (to make pastry in a food processor, simply add ingredients in the same order).

3. Roll out pastry on a lightly floured work surface and use to line 4 tartlet tins, trim away excess pastry. Cut squares of parchment paper to line and fill the pastry cases with baking beans. Bake blind in an oven pre-heated to 170°C for 15 minutes until the pastry is par-baked. Remove from oven and remove paper and beans.

4. For the chocolate custard filling. In a small heavy based pan, heat the cream and milk until they just reach boiling point.

5. Place the chopped chocolate in a bowl and pour the hot cream and milk over the chocolate. Leave to stand for 1 minute, then stir until smooth and combined.

6. In a separate bowl, use a hand whisk to whisk together the egg yolk and sugar. Next stir in the chocolate cream mixture until combined.

7. Pour the chocolate custard into the par-baked tartlet shells.

8. Bake on the middle shelf of the preheated oven and bake for 12-15 minutes until just set.

9. Remove from the oven and allow to cool. Serve chilled with whipped cream or a small quenelle of vanilla ice cream.

Variation: Add the seeds from a vanilla pod to the heated milk for a luxurious flavour. Alternatively add a dash of strong espresso coffee to enhance the flavour.