|For the pastry: |
| 1 lb 2 oz (500 g) ready-made puff pastry|
| a little flour, for dusting|
| 1 large egg yolk, lightly beaten, to glaze|
| ¾ oz (20 g) finely grated Parmesan |
|For the filling: |
| ¾ oz (20 g) dried porcini mushrooms|
| 9 oz (250 g) chestnut mushrooms, roughly chopped|
| 9 oz (250 g) oyster mushrooms, roughly chopped|
| 5 fl oz (150 ml) dry (seco) Madeira|
| 1½ oz (40 g) butter|
| 1 large onion, finely chopped|
| 3 cloves garlic, crushed|
| 1 rounded tablespoon plain flour|
| ¾ teaspoon chopped fresh thyme|
| whole nutmeg|
| 3 fl oz (75 ml) double cream|
| a few sprigs watercress, to garnish|
| salt and freshly milled black pepper |
|To serve: |
| Foaming Hollandaise Sauce (see link, below)|
|You will also need 2 medium, solid baking trays, lightly greased.|
Begin by making the filling: put the dried mushrooms in a jug and cover them with 10 fl oz (275 ml) of boiling water, then leave them to soak for 30 minutes. Now melt the butter in a large saucepan and soften the onion and garlic in it till pale gold (about 5 minutes). Then stir in the flour, followed by all the fresh mushrooms, the soaked mushrooms (snipped a bit with a pair of scissors, if they’re large) and their soaking water. Season with salt and pepper and add the thyme and a few gratings of nutmeg.
Now pour in the Madeira, cover the pan with a tight-fitting lid and let the mushrooms cook as slowly as possible for 1½ hours: the liquid should barely simmer, and you should check and stir it from time to time to make sure the liquid hasn’t evaporated.
Now divide the pastry in half and, on a lightly floured surface, roll one half into a 5- x 15-in (13- x 39-cm) strip, about ¾-in (2-cm) thick, then cut this into three 5- x 5-in (13- x 13-cm) squares. Repeat with the remaining pastry, so you end up with 6 squares. Then transfer 3 squares to each baking tray and brush each one with egg yolk. Next, using a sharp knife, carefully score a line all the way around the inside of each square, about ¾ in (2 cm) in from the edge, being careful not to cut all the way through. Now sprinkle each one with Parmesan and transfer the trays to the fridge to allow the pastry to rest for 30 minutes. Pre-heat the oven to gas mark 7, 425°F, 220°C.
Bake the pastry on a high shelf in the oven for 12-14 minutes, or until golden brown and crisp. Then remove from the oven and transfer the squares to a wire cooling rack. Using a small sharp knife, cut around the scored line on each square and remove the lids. If there is any uncooked pastry in the centre, scrape it out. Then leave the pastry cases and lids to cool.
To serve, warm the pastry in a low oven and re-heat the foaming hollandaise over a saucepan of barely simmering water. Stir the cream into the mushrooms and re-heat them. Put each parcel on to a warm plate and fill with mushrooms. Replace the lids and spoon a little sauce over each one; serve the rest separately in a warm jug. Garnish with watercress and serve straight away.