Autumn summed up in a tart, both in flavour and appearance. I have used the woodland mushroom mix, sold in Waitrose and often called exotic mushroom mix in Tesco and Sainsbury. Swap these fungi for some wild mushrooms if you are lucky enough to find them and, at a push you can use chestnut mushrooms but you will lose a little flavour and texture. I like to eat this tart at room temperature with a salad of bitter winter leaves-the perfect plateful.
200g plain flour
100g butter, cut into cubes
¼ teaspoon fine salt
For the filling
2 medium leeks, trimmed, washed and finely sliced
2 x 200g packs woodland mix mushrooms (see intro)
2 teaspoons dried dill ( or 2 tablespoons finely chopped fresh dill)
300ml pot sour cream
Put the walnuts in a food processor and blend to fine breadcrumbs. Tip into a large mixing bowl.
Put the flour, butter and salt in the food processor (no need to clean it) and pulse to blend the butter into the flour until no visible lumps remain. Tip into the bowl with the walnuts and mix well. Add about 3 tablespoons cold water and bring the dough together to form a ball. Press out to a rough circle and wrap in cling film. Chill for 30 minutes.
Meanwhile make the filling. Melt 35g of the butter in a saucepan and add the leeks. Cook over a gentle heat for about 15 minutes, stirring regularly, until really soft but not coloured. Set aside.
Cut off any mushroom stalks and discard. Heat the remaining butter in a frying pan and fry the mushrooms in small batches for 4-5 minutes. Set aside.
Roll the pastry out between two sheets of baking parchment to a circle large enough to line a 23cm tart tin. Chill for 30 minutes. Heat the oven to fan 170°c, mark 4.
Bake the pastry blind for about 25 -30 minutes until the sides are light golden. Remove the lining and baking beads and return to the oven for about 10 minutes until the base is firm. Reduce the oven temperature to fan 150°c, mark 2.
Spread the leeks over the base of the tart. Arrange the mushrooms on top. In a large jug beat the eggs with the dill, ¼ teaspoon salt and some ground black pepper. Stir in the sour cream. Pour into the tart and smooth to the edges. Bake in the oven for 30-35 minutes or until the centre feels just firm to the touch.