First make the pastry. Sift the flour into a bowl. Add the butter and rub into the flour until well blended and the mixture resembles fresh breadcrumbs. Stir in 25ml (5 tsp) caster sugar.

Add the egg yolk and mix in. Bring together with your hands, pressing the ingredients together to make a ball. Turn on to the work surface and knead gently until smooth and well combined.

Lightly flour the work surface and roll out the pastry thinly – approx. 2mm (1/8th inch). Using a 9cm (3 ½ inch) plain round cutter, stamp out 12 rounds, re-rolling as necessary.

Carefully fit each circle of pastry into a 12 cup fairy or cup cake tin, approx. 2.5cm (1inch) deep. If the pastry splits as you fit it into the tins, carefully press the pastry back together – it is important that there are no cracks. Neaten the edges. Chill for 30 minutes.

Preheat the oven to 180°C (160°C fan oven, 350°F, gas mark 4). Meanwhile, make the custard. Put all the ingredients in a jug and whisk together until well blended. Set aside.

Once the pastry cases are chilled, whisk the custard again and carefully pour into each of the cases, making sure you don't fill them right to the top. Sprinkle nutmeg on the the top of each and bake for 20-25 minutes until very lightly golden, firmish but still wobbling slightly – the custard will set further on cooling. Leave in the tins for 15 minutes or until firm enough to loosen the edge with the blade of a knife. Transfer to a wire rack to cool.

To serve, these custard tarts are delicious eaten at room temperature but for a firmer custard and pastry, chill for 1 hour before serving.