Salmon and Spring Vegetable Tourte

Make the pastry: combine the flour and salt in a large bowl. Add the cold butter cubes and rub in with your fingertips until the mixture resembles coarse breadcrumbs with some pea-sized pieces remaining. Add the beaten egg and 3 tablespoons of ice-cold water, then mix with a fork, adding water a tablespoon at a time until the dough just comes together. Divide into two discs — one slightly larger than the other — wrap, and refrigerate for at least 1 hour.

Toss the salmon chunks with the fine sea salt, spread on a paper-towel-lined plate, and leave uncovered to rest at room temperature for 30 minutes, then pat completely dry with fresh paper towels.

Meanwhile, slice the leeks, dice the shallots, mince the garlic, prepare the asparagus, and chop the tarragon and parsley. Zest and juice the lemon. Mix the egg yolk and milk together for the egg wash and set aside.

Heat the butter and olive oil in a wide sauté pan over medium heat until the butter foams. Add the shallots and leeks and cook, stirring occasionally, until fully softened and any liquid has evaporated, about 12 minutes — the leeks should be silky and just beginning to colour at the edges.

Add the garlic and asparagus to the pan and cook, stirring, until the asparagus is bright green and just tender, about 4 minutes.

Remove the pan from the heat. Stir in the peas, crème fraîche, Dijon mustard, tarragon, parsley, lemon zest, lemon juice and white pepper. Fold in the dried salmon pieces, taste, and adjust the seasoning. Spread the filling onto a large tray and leave to cool completely to room temperature.

Preheat the oven to 200°C, or 180°C for a fan oven, or 400°F with a heavy baking sheet inside on the middle rack.

On a lightly floured surface, roll the larger pastry disc into a circle about 30cm in diameter. Lift it carefully into a 22cm round deep pie tin (at least 5cm deep), pressing it into the base and sides and allowing the excess to overhang. Spoon in the cooled filling, mounding it slightly in the centre.

Roll the second pastry disc into a 24cm circle and lay it over the filling. Trim the overhang to 1.5cm, fold the edges together, and crimp firmly to seal. Cut a 1.5cm steam hole in the centre and brush the entire surface with egg wash.

Slide the tourte onto the preheated baking sheet and bake until the pastry is deeply golden and the filling registers 63°C on a meat thermometer inserted through the steam hole, about 40 minutes — the base should sound hollow when tapped. Rest the tourte in the tin for 15 minutes before slicing and serving.