Not mushroom for error pie with duck fat pastry
Mushrooms are perfect in pies because they keep their shape and take on all the other flavours. I love the depth you get here from frying them down – so meaty, textural and savoury – and the bonus flavour from using duck (or goose) fat in the pastry, or even just the fat (schmaltz) left behind after roasting a chook. You can of course simply use extra butter in the pastry, or use a quality frozen shortcrust pastry and mix some duck or chicken fat through the mushroom mixture to enhance the flavours. If you can’t find porcini powder, blitz some dried porcini mushrooms in a blender, or rehydrate them, squeeze out the excess water (and use it in the pastry) and toss through the mushroom mixture.
WHAT YOU NEED
For the filling
750 g (1 lb 10 oz) mixed mushrooms, thinly sliced (we used button and portobello)
40 g (1½ oz) butter
1 leek, pale part only, finely sliced
1 brown onion, finely sliced
2 tablespoons dried porcini powder
1 teaspoon dried tarragon
½ teaspoon ground nutmeg
1 tablespoon salt flakes
¼ cup (35 g) plain (all-purpose) flour
2 tablespoons sherry vinegar
1 egg yolk, lightly beaten
good-quality tomato sauce, to serve
For the duck fat pastry:
3 cups (450 g) plain (all-purpose) flour, plus extra for dusting
1 teaspoon freshly cracked black pepper
1 teaspoon salt
100 g (3½ oz) duck fat or rendered chicken fat
100 g (3½ oz) salted butter, chopped
2 tablespoons sour cream
2 tablespoons apple cider vinegar
WHAT TO DO
For the pastry, combine the flour, pepper and salt in a bowl. Toss the duck fat and butter through. Using just your fingertips, gently rub them into the flour until the mix resembles coarse crumbs. Make a well in the centre. Pour in the combined sour cream, vinegar and ¼ cup (60ml) cold water then, using a small knife, cut together to form a dough, taking care not to overwork it. Transfer to a lightly floured work surface and knead into a ball, then divide into three evenly sized balls. Flatten into discs, then wrap and chill in the fridge for 1 hour.
Meanwhile, make the filling. Pop the mushrooms in a large frying pan over high heat with enough water to cover. Allow the liquid to boil and evaporate completely, listening for the sizzle. Add half the butter to the pan and toss the mushrooms until golden, then set aside. In the same pan, sweat the leek and onion in the remaining butter until softened. Add the mushrooms back, sprinkle in the porcini powder, tarragon, nutmeg and salt, stir in the flour, splash in the vinegar and cook, stirring, for about 3 minutes, or until your eyes stop stinging.
Grease a deep 27 cm (10¾ inch) pie dish or baking tin. On a lightly floured work surface, roll out one piece of pastry to a 3 mm (½-inch) thick round, then use the rolling pin to lift it over the dish and press it in with your fingers. Roll the remaining pastry into long rectangles about 3 mm (‑ inch) thick, cut into 2–3cm (¾–1¼inch) wide strips and transfer to a lined tray. Chill all the pastry in the fridge again for 15 minutes. Use this time to shape any excess into decorative pastry mushrooms.
Meanwhile, preheat the oven to 200°C (400°F).
Fill the pie base with the mushroom mixture.
Arrange the pastry strips in a lattice pattern over the filling, pressing the sides and strips together to seal.
Place the pie dish on a baking tray and brush the pastry with the beaten egg yolk. Arrange any decorative pastry mushrooms on top and brush again. Bake for about 45 minutes, or until the pastry is golden.
Cool slightly, then serve warm, with tomato sauce.