Jason Atherton’s Marmite tarts

Method

1. For the pastry, add the flour, cornflour, sugar and salt to the bowl of a stand mixer with a paddle attachment. Mix to combine, then add the butter and mix at a slow speed for about 5 minutes until it forms a breadcrumb-like consistency.
2. Add the remaining pastry ingredients (except 1 whole egg) and mix until a dough forms. Turn out onto a flour-dusted work surface and knead briefly to form a fat disc. Wrap well and leave to rest for 2 hours at room temperature.
3. Unwrap the dough and divide into 4 portions (around 250g each). Put one portion between 2 sheets of baking paper and roll it out to around 2.5mm thick. Transfer to the fridge, then repeat with the other portions. Leave the rolled dough in the fridge for 2 hours.
4. Meanwhile, make the filling. Put all the ingredients in a blender, then whizz until smooth and combined. Pour the mixture into a large pan and set over a medium heat. Cook, stirring regularly, until the mixture reaches 60°C. Try to keep it at this temperature for 5 minutes to cook it through, then strain through a fine sieve into a bowl. Cover the surface with baking paper (so the paper is touching the custard) and set aside at room temperature until needed.
5. Heat the oven to 185°C/165°C fan/gas 4½. Line the tart tins for pastry rings with the chilled pastry, leaving a little overhang, then prick the bases all over with a fork. Fill each tart case with baking paper and baking beans or rice, then blind-bake for 20-25 minutes. Remove the beans/rice and paper and bake for another 3 minutes until the pastry is golden and crisp.
6. Turn the oven down to 140°C/120°C fan/gas 1. Trim the edges of the tarts (a fine Microplane grater gives the neatest results), then beat the remaining egg and brush it all over. Return the tarts to the oven for 1 minute to set the egg, then remove from the oven.
7. Pour the Marmite custard into the tart cases, then carefully return them to the oven. Bake for 20 minutes – they will still have a good wobble but should be just set. Leave to cool to room temperature for 30 minutes, then sprinkle generously with caster sugar. Use a blowtorch to caramelise the sugar on top (like a crème brûlée), then serve (topped with caviar if you’re feeling particularly bougie).