Chocolate orange pithivier

Method

1. Heat the oven to 180°C fan/gas 6. Line 2 large baking sheets. Put the hazelnuts on a separate baking tray and roast for 10 minutes. Set aside to cool, then whizz in a food processor until finely ground.
2. Roll out the puff pastry on a lightly floured work surface to a 45cm x 25cm rectangle. Cut out 2 discs, one measuring 20cm, the other 25cm in diameter. Transfer to the prepared baking sheets, then chill for 20 minutes.
3. For the filling, beat the butter and sugar with an electric hand mixer until pale and fluffy. Beat in the whole egg and one yolk until well combined. Fold in the ground hazelnuts and flour, then the chopped chocolate.
4. To assemble, spread the conserve over the smaller pastry disc, leaving a 2.5cm border. Spread the chocolate/hazelnut filling on top in an even layer, maintaining the 2.5cm border.
5. Beat the remaining egg yolk with 1 tsp water and brush it over the pastry border. Lay the larger pastry disc over the filling, releasing any trapped air and pressing the edges to seal. Chill for 20 minutes. Increase the oven temperature to 200°C fan/gas 7.
6. Remove the pithivier from the fridge and press once more to ensure the pastry is well sealed. Brush the top with the remaining egg wash. Using the tip of a small, sharp knife, score radial arcs into the pastry, working from the centre outwards and taking care not to cut all the way through.
7. Bake for 15-20 minutes until puffed and golden. Turn down the oven to 160°C fan/gas 4 and bake for 35 minutes more until the pastry is deep golden. If it starts to brown too much, lay a sheet of foil loosely over the top. Cool slightly and serve warm.