First, make the filling. Heat the oil and butter in a saucepan over a medium-low heat and fry the shallots for 6-8 mins until softened and beginning to brown. Stir in the mushrooms and cook for a further 5-6 mins until they’ve released their liquid and it’s mostly evaporated. Add the cumin and coriander and cook for 1 min, then pour in the white wine and simmer for a few minutes to cook the alcohol off.

Stir in the spinach and cook until wilted, then mix in the rice, lemon zest and juice and the herbs. Cook for a few minutes to allow everything to combine. Remove from the heat and set aside.

Heat the oven to 220C/200C fan/gas 7. Unwrap one sheet of pastry and unroll on a large baking tray. Season the salmon all over with salt and pepper, then lay the fillets side by side on the first piece of pastry, leaving a 3cm border around the edge. Top with the rice filling. Glaze the edges of the pastry with some of the beaten egg.

Unwrap the second piece of pastry and lay over the top, pulling gently so the edges meet the bottom piece of pastry. Crimp the edges together with a fork. Lightly score the pastry with a pattern, if you like (make sure you don’t go all the way through). Glaze the pastry all over with more beaten egg and bake in the oven for 20 mins.

Reduce the oven temperature to 200C/180C fan/gas 6 and cook for a further 20 mins, until the pastry is golden and puffed up. Leave to rest for 10 mins before serving.