Preheat the oven to 200°C/180°F/ Gas 6. To make the pastry, tip the flour into a large bowl, then rub in the butter with your fingertips until the mixture resembles breadcrumbs. Stir in the icing sugar, then add the egg and mix well to form a dough. Turn it out onto a lightly floured surface, knead, then cover with cling film and put in the fridge to chill for 20 minutes.
Remove the pastry from fridge and roll it out on a lightly floured surface. Cut 12 rounds large enough to fill your tart tins with overlap and place them in the tins. Sit the tart cases back in the fridge for 15 minutes. When ready to bake, fill each one with baking parchment and beans and place in the oven for roughly 10-15 mins, remove, then carefully cut away the overlap. Reduce the oven to 180°C/160°F/Gas 4.
To make the filling, add the cream to a pan and heat gently. When hot, remove from the pan and add the chocolate. Stir until melted, then add the egg yolks. Fill each tart case to the top with the mixture, then bake until the mixture sets and the pastry is golden. Remove from oven and leave to cool.
Meanwhile, add the sugar to a pan with two tablespoons of water until the sugar dissolves. Decorate the tartlets with strawberry slices and brush each with the sugar mixture. Scatter with pistachio nuts and serve with a trickle of cream or a dollop of crème fraiche.
40 minutes 
Serves 5
