“The jalousie has many incisions made in the pastry to let the steam out, so the pastry can crisp. A large version of this old-fashioned pie is very good, but when made smaller, cooked crisp, cooled then sliced, it makes excellent bites with drinks. ”
Soak the porcini in water for 30 minutes. Peel and finely chop the shallots and the garlic, then cook in the butter (or oil) in a pan. Drain the soaked porcini, chop, add to the shallots and cook gently for 10 minutes, then add the flat mushrooms. Cook until the mushrooms are bubbling away. Add the wine, thyme and summer savory, season with salt and black pepper and cook for a further 5–10 minutes, until no trace of liquid remains. Remove from the heat, take out the thyme and add the parsley and Parmesan. Spread the mushrooms on a flat tray and let cool. (This can be made the day before, very much to its benefit, I find.)
Preheat the oven to 200°C.
Roll half the pastry out quite thin and cut into two long strips, 5cm wide, 30cm long. Lay these on a baking sheet lined with baking parchment. Roll out another two lengths with the other half, 1cm wider. Fold these in half lengthways and make incisions every 2mm along the length of the pastry except for 1cm at each end.
Form the mushroom mixture into the shape of a rod and lay along the middle of the pastry (the strips on the baking parchment) from one end to the other, leaving a 1cm border each side. Lightly brush the edges with egg wash. Take the lengths of cut pastry and lay them over the mushroom filling, pressing lightly round the edges until aligned, trimming the edges to neaten if necessary. Egg wash the surface and fully press down the edges with the tines of a fork. Refrigerate for at least 30 minutes. (These can be made the day before.)
Place the tray in the heated oven and lower the heat to 180°C. Bake for 30 minutes, until well coloured and crisp. Remove from the oven and cool before slicing and serving.
These are best eaten just warm. A flourish of freshly grated Parmesan atop is a happy consideration.