Chocolate orange tart

1. In a bowl, using your fingertips, rub the 100g cubed butter into the flour with a pinch of salt until it resembles fine breadcrumbs. Add 1 egg yolk and 1 tbsp cold water. Using a blunt-edged knife, draw the mixture together. When it starts to clump, bring the pastry together with your hands, adding a sprinkle of water to any dry patches. Knead into a smooth disc. Wrap and chill for at least 20 minutes.

2. Preheat the oven to 200˚C, gas mark 6. On a lightly floured surface, roll out the pastry to 0.3cm thick and use to line a 20cm round fluted tart tin. Trim the excess, then pinch the pastry sides up to just above the top edge of the tin. Use a fork to prick holes in the base. Line with baking parchment, fill with baking beans, then bake on a baking tray for 18 minutes. Remove the parchment and beans; bake for 10-12 minutes, until golden and crisp. Set aside in the tin to cool completely.

3. Meanwhile, pare the zest of ½ an orange, finely shred and set aside. Zest the remaining 2½ oranges with a fine grater and juice enough to measure out 120ml. Beat the remaining egg yolk and whole egg, then put in a pan with the sugar, grated zest, orange juice, cornflour, remaining 40g butter and a pinch of salt. Over a low-medium heat, gently stir the ingredients with a rubber spatula until the butter has melted and the sugar dissolved. Cook for 18-20 minutes, stirring, until it is the consistency of thick custard. Sieve into a bowl and set aside to cool for 15 minutes. Transfer the pastry case to a serving plate, then pour in the orange curd and spread into an even layer. Cover with a large bowl and chill for 2 hours.

4. Put the chocolate in a bowl. In a small pan, heat the cream gently until steaming and starting to bubble at the edge of the pan. Remove from the heat before it boils and pour over the chocolate. Allow to stand for 1 minute, then stir until just combined (be careful not to overmix as it could turn grainy). Immediately pour evenly across the surface of the tart and spread into an even layer. It’s important to work quickly; when the chocolate hits the curd, it will start to set. Scatter over the pared orange zest. Chill for at least 30 minutes (it will keep chilled for up to 2 days), then serve scattered with a little flaky sea salt.