Fill a piping bag fitted with a round tip (about 2.5 cm) and pipe 'logs' roughly 10 cm long onto a baking sheet lined with parchment paper. Leave plenty of space between each piece, as the pastry puffs up quite a bit.

Take the shortcrust dough out of the fridge, knead briefly, then roll it out to a thickness of 1–2 mm. Cut out rectangles about 4 cm x 12 cm and place one on top of each piped choux 'log'.

Bake in an oven preheated to 180°C until golden. In my oven this took about 30 minutes. Remove from the oven and let cool completely before filling.

Whisk together the egg yolks and sugar, then add the cornstarch and beat until the mixture is pale yellow and thickened. Pour the milk into a saucepan. Split the vanilla pod lengthwise, add the seeds to the milk and bring to the boil.

Slowly pour the hot milk into the egg yolk mixture, whisking constantly. Pour everything back into the saucepan and bring to the boil, stirring all the time. Cook until the mixture thickens, then whisk in the butter. Cover with plastic wrap and let cool.

Whip the cream and fold it into the cooled custard cream. Fill the prepared eclairs by piercing three small holes with the piping tip and injecting the cream inside. Dust with powdered sugar just before serving.

Eclairs are best filled right before serving – if you leave them filled in the fridge for too long, the pastry turns soggy and loses its charm. Store the unfilled shells in an airtight container.