Chocolate, hazelnut and cherry tart with burnt meringue

Method

1. For the pastry, whizz the flour, butter and a pinch of salt in a food processor until the mixture resembles breadcrumbs. Pulse in the sugar, then add just over half the egg yolk mixture; pulse until the pastry starts to come together. If it looks a bit crumbly, add a bit more egg until it forms a soft dough. Tip out onto a lightly floured surface and bring together with your hands. Knead very briefly until pliable, then shape into a fat disc, wrap in cling film and chill for 1 hour.
2. Heat the oven to 190°C/170°C fan/ gas 5. Remove the pastry from the fridge and roll out on a floured surface to the thickness of a £1 coin. Use to line the tart tin, pressing it into the edges. Roll a rolling pin over the top to cut off the excess, then push the pastry gently into each flute to secure. Chill in the fridge for 30 minutes or the freezer for 15.
3. Once the pastry is firm, line with foil or baking paper and fill with baking beans or rice, then bake for 20 minutes in the middle of the oven. Remove the beans/rice and foil/ paper, then bake for 5 minutes or until the pastry is crisp and sandy- coloured with no grey patches.
4. Turn the heat down to 170°C/ 150°C fan/gas 3½. Brush the inside of the pastry case all over with the beaten egg whites, then return to the oven for 5 minutes. This will form a waterproof barrier between the filling and the pastry, keeping the base and sides crisp. Leave the pastry to cool completely in the tin.
5. To make the filling, turn the oven back up to 180°C/160°C fan/gas 4. Lay the hazelnuts out on a baking tray and toast in the oven for 10 minutes or until deep golden. Whizz in a food processor for 4-5 minutes, scraping down the sides occasionally. The hazelnuts will start to release their oils and turn into hazelnut butter (just a little bit rougher than smooth peanut butter). Once this happens, whizz through the unsalted butter and a large pinch of salt until smooth.
6. Put the chocolate, double cream and sugar in a large heatproof bowl set over a pan of very gently simmering water (just the odd bubble is what you’re looking for). The base of the bowl shouldn’t touch the water. Allow to melt very slowly, stirring occasionally, until the chocolate has almost entirely melted. Stir gently, leave until there are no lumps visible, then remove from the heat and transfer to the food processor with the hazelnut mixture. Whizz together until combined and smooth.
7. Tip the cherries into the pastry case, then spoon over the chocolate mixture and smooth the surface. Cover the tart very loosely with foil (try not to let it touch the surface) and chill for at least 2-3 hours until the filling is firm (it will keep for up to 48 hours at this stage; see Make Ahead).
8. For the meringue, put the egg whites in a large heatproof bowl and whisk briefly with an electric mixer to combine. Sift in the icing sugar, then whisk until well combined. Set the bowl over a pan of gently simmering water and whisk until you have a thick, stable meringue – it shouldn’t move at all when you move the bowl. Remove from the heat and whisk in the cornflour until smooth, then leave to cool a little.
9. Once the tart is firm, remove from the fridge around 30 minutes before you want to serve. Spoon the meringue into the centre of the tart, swirling it into peaks as you go. Take the tart to the table and, using a chef’s blowtorch, brown the outside of the meringue just before serving to “oohs” and “aahs”.