Mushroom, Rye and Preserved Lemon Pithviers

Put the pastry on a lightly floured kitchen bench and roll it out into a rectangle measuring 30 × 65 cm (12 × 25½ in) and 3 mm (⅛ in) thick. Working along the length of the pastry, cut out four small discs 13 cm (5 in) in diameter for the base, and four larger discs 15 cm (6 in) in diameter for the tops. Lay the pastry between two sheets of baking paper and refrigerate for 20 minutes, or until you are ready to assemble the pithiviers.

Melt half of the butter with half of the olive oil in a medium frying pan over a medium heat. Add the onion, garlic, thyme, and rosemary, and cook with the lid on, stirring occasionally, for about 10 minutes, or until soft and translucent.

Meanwhile, melt the remaining half of butter and olive oil in a large frying pan over a medium heat. Fry the mushrooms for 4–5 minutes until they start to turn golden. You may need to do this in batches depending on the size of your pan. Add a squeeze of lemon juice as you finish cooking each batch, then transfer the mushrooms to a colander set over a bowl to drain. Set aside to cool.

Combine the mushrooms, onion mixture, parmesan, preserved lemon, salt and pepper in a large bowl. Taste and check for seasoning and adjust to your taste. Set aside for 1 hour, or overnight, to cool and allow the flavours to marry.

To assemble, divide the mushroom mixture into four equal portions, about 150 g (5½ oz) each. Cup your hands over the mushroom mixture to form a tight ball, repeating for each portion. Put them on a tray and chill in the fridge while you get your pastry ready.

Line a baking tray with baking paper. Lay the larger pastry discs on a floured bench and mark the centre of each with a tiny vent hole. Using a pastry cutter or small plate as a template, very lightly score curved lines in the disc, starting from the centre to the edge of the pastry, moving the template around until you have filled the disc. You can do a few curved lines or a lot – get creative!

Lay the smaller pastry discs on the bench and place one portion of mushroom filling in the middle of each. You might feel like there’s too much filling, but it’s worth piling it up now as it will reduce during baking. Lightly brush around the pastry edges with egg wash, then lay the large discs over the filling.

Carefully push the pastry lid down and around the mushrooms, cupping your hands around the filling to seal and straighten it, edging out any air as you go. The edge of the top disc should sit flush with the edge of the bottom disc; carefully ease the top layer out with your fingers if needed. Pinch the edges together with your finger and thumb to seal and crimp the edges. You can also use a fluted pastry cutter or fork to seal and decorate the edges.

Transfer the pithiviers to the lined tray. Lightly brush the tops with egg wash and refrigerate for 1 hour, or overnight, to set the butter back into the pastry and let the egg wash set.

When you’re ready to bake, preheat the oven to 190°C (375°F). Bake for 15 minutes, then reduce the oven to 180°C (360°F) and turn the tray. Bake for a further 20 minutes, or until golden. Transfer to a wire rack to cool for 10 minutes before serving.