Charred clementine tart

1. Preheat the oven to 170˚C, gas mark 3. For the pastry, put all the ingredients in a food processor. Pulse the mixture until the pastry resembles a fine crumble (be careful not to overwork). Turn the mixture out onto a cool surface and work into a log shape. Wrap in cling film and put in the fridge until cold (for about 1 hour).

2. Brush a deep 25cm tart tin with a little oil. Roll out the pastry on a floured surface to a 5mm thickness and round shape. Place in the tin and press gently into the edges (you can patch up holes or cracks if it breaks). Prick the base with a fork. Line the case with baking parchment and baking beans then return to the fridge for 30 minutes to chill.

3. Bake the pastry case in the oven for 30 minutes, then remove the baking beans and parchment and cook for a further 10-12 minutes, or until golden brown. Allow to cool. Meanwhile, make the filling. Toss the zested clementine and lemon halves with the oil and put, flesh side down, in a hot frying pan. Leave until charred – around 5 minutes. Allow the fruit to cool, then squeeze the juice out, pass through a sieve (making sure some of the blackened bits make it through; you should have about 200ml juice) and combine with the zest.

4. Soak the gelatine leaves in iced water. In a large bowl, whisk the eggs and yolks together with the sugar, then set over a pan of simmering water with the butter, citrus zest and juice. Cook over a low heat, stirring constantly. It is ready when it reaches 70˚C on a sugar thermometer. Take off the heat and whisk in the gelatine leaves. Pour the mixture into the tart case. Chill for 2-3 hours before slicing.