225g (8oz) butter – cold and cut into small pieces
150g (5oz) whole walnuts – shelled
15g (½ oz) fresh chives – finely chopped
5 tbsp water – ice cold
1 egg - beaten
For the filling…
30g (1oz) dried porcini mushrooms
60g (2oz) butter
1 tbsp walnut oil
2 onions – roughly chopped
5 garlic cloves - sliced
1kg (2¼lb) small chestnut mushroom
5 tarragon stalks – leaves only
1 tbsp soy sauce
5 tbsp marsala
4 tbsp double cream
2 tbsp ground almonds
2 tbsp parsley – finely chopped
300g (11oz) baby spinach
Freshly grated nutmeg
1 red chilli – dried or crushed
Preheat the oven to 200°C / 400°F / gas mark 6.
Sift the flours and salt together, stirring any brand back that's been left in the sieve.
Lightly and deftly rub in the butter, adding the roughly chopped walnuts and finely chopped chives.
Bring the pastry together by slowly adding 1 tablespoon of cold water at a time, up to 5 tablespoons in total.
Shape the pastry into a ball with the palm of your hand, wrap it in cling film and chill for 30 minutes, or place in the freezer for 15 minutes.
Roll out two thirds of the pastry on a lightly floured surface and carefully lift into a lightly buttered and floured pudding basin. Press over the sides, leaving a slight overhang.
Refrigerate again for another 30 minutes.
Bake in the oven for about 20 minutes until golden and crisp.
Set aside to cool so it doesn't go soggy when you add the filling.
Meanwhile, from the remaining pastry (reserving some for decoration, roll out one circle for the lid, using the pie tin as a guideline and set aside.
Make some pastry holly leaves and a long strip to fit all the way around the top of the pie. Set aside.
To prepare for the filling, soak the dried porcini mushrooms in 150ml hot water with a dash of soy sauce and a dash of Marsala.
Make the rest of the filling by heating the butter and walnut oil in a large frying pan and adding the chopped onion. Fry on a gentle heat for a good 20 minutes, stirring frequently, until the onion is soft and starting to turn golden.
About half way through the frying, add the sliced garlic, but keep a watchful eye on it. It should turn transparent, not brown.
Now add the shitake and chestnut mushrooms briskly washed of any earth, to the pan of fried onions and fry for 15 minutes on a medium to high heat. Salt them lightly.
Strain the softened porcini mushrooms and reserve the soaking liquid. Add the mushrooms, strained liquid, soy sauce, half the tarragon, the Marsala and double cream and cook together for 4 to 5 minutes.
Using a slotted spoon, fish the mushrooms out and set aside a while whilst you increase the heat to reduce the cream sauce by half so that it is thick and creamy.
Return the mushrooms to the sauce, discarding any extra liquid that may have wept from the mushrooms in the meantime and heat through, adding the remaining tarragon and stirring in the ground almonds to thicken the sauce.
Finally add the chopped parsley.
Transfer the mushrooms and sauce to a bowl.
In the same frying pan, using any sauce that remains, wilt the spinach for about 3-4 minutes on a moderate heat. Season with salt and pepper, a good pinch of finely grated nutmeg and the dried red chilli.
Cool then loosen the spinach with your fingers and place on the pastry base to completely cover it.
Now pile in the mushrooms and sauce and cover with the reserved circle of pastry. Decorate with the leaves and place the strip around the top, gluing with a little beaten egg and crimp to a fluted crown all the way round.
Glaze the pie with beaten egg and bake in the oven for 35 to 40 minutes until golden and crisp.
Let it rest for ten minutes, then carefully turn out the heavy pie onto a serving plate to a ceremony of oohs and ahhs.