Mushroom, Walnut and Cheese Tourte

Combine the dried porcini and boiling water in a small bowl and set aside to rehydrate for 20 minutes, then drain, reserving 3 tablespoons of the soaking liquid. Finely chop the rehydrated porcini.

Lightly flour a work surface and roll one portion of pastry into a 30cm round, about 3mm thick. Line a 22cm springform or deep pie tin, pressing into the edges and trimming any overhang to 1cm. Roll the second portion to the same size for the lid. Refrigerate both, uncovered, for 30 minutes.

Toast the walnuts in a dry frying pan over medium heat, stirring frequently, until fragrant and lightly golden, about 4 minutes. Tip onto a plate.

Melt the butter with the olive oil in a wide, heavy-bottomed pan over medium-high heat until the foam subsides. Add the shallots and cook, stirring occasionally, until softened and translucent, about 4 minutes.

Add the garlic, thyme and rosemary and cook, stirring constantly, until fragrant, about 1 minute.

Add all the fresh and rehydrated mushrooms to the pan. Increase the heat to high and cook, stirring only occasionally, until the mushrooms have released all their liquid and the pan is completely dry with the mixture beginning to caramelise, about 15–18 minutes.

Pour in the sherry and the reserved porcini soaking liquid. Cook, stirring, until fully evaporated and the mixture is nearly paste-like, about 3 minutes. Season with salt and pepper, then remove from the heat and leave to cool completely, about 20 minutes.

Preheat the oven to 200°C, or 180°C for a fan oven, or gas mark 6 with a heavy baking sheet on the middle shelf. Whisk together the eggs, crème fraîche, Dijon mustard and nutmeg in a bowl, then stir this into the cooled mushroom duxelles and fold in the Gruyère, Comté and toasted walnuts until evenly combined.

Spread a thin layer of mustard over the base of the chilled pastry case. Spoon in the filling, pressing it down firmly and levelling the surface. Drape the pastry lid over the top, press the edges together firmly to seal, trim to a neat border, and crimp with a fork. Cut a 2cm steam vent in the centre.

Brush the lid evenly with egg wash. Place the tin on the preheated baking sheet and bake until the pastry is deep golden and the vent releases steady wisps of steam, about 40 minutes. Rest the tourte in the tin for 15 minutes before unclipping and slicing.