1.5 quantities (750g) firm ultimate savoury pastry (see below) or 750g store-bought shortcrust pastry 40g dried mushrooms (we used porcini) 1kg mixed mushrooms, thinly sliced 1/3 cup (50g) plain flour 1/2 cup (125ml) sherry 1/2 tsp ground nutmeg 50g parmesan, finely grated 1 cup (240g) sour cream 1 tbs grated or creamed horseradish 1 tbs…