Mushroom and époisses pithiviers

Method

1. Heat a good drizzle of oil in a frying pan over a high heat. Add the flat mushrooms, stalk-side up, season, then fry for 3-4 minutes until golden. Turn them, then fry for another 3-4 minutes, pressing down with a spatula to brown evenly.
2. Put the fried mushrooms in a colander, leaning them against the sides so any liquid can run out. When most of the moisture has gone, dry the mushrooms using kitchen paper. Leave to cool, then chill on a plate lined with more kitchen paper.
3. Meanwhile, clean the frying pan and melt two thirds of the butter. Add the chopped mushrooms and season well. Fry on a high heat, stirring now and then, until golden and shrunken. Remove to a plate. Reduce the heat, then add the remaining butter to the pan and gently fry the shallot and garlic for 4-5 minutes until translucent.
4. Return the chopped mushrooms to the pan, turn the heat back up to high, then pour in the madeira and sherry vinegar. Bubble until all the liquid has evaporated. Stir through the sage leaves, then transfer everything to a plate to cool.
5. Put the flat mushrooms stalk-side up on a board, then cut away the stalk and some of the flesh to make a small well. Stir the époisses chunks into the cooled mushroom mixture, then press half of it onto each flat mushroom. Top with the sliced époisses, then season.
6. Preheat the oven to 200°C/fan 180°C/gas 6. On a lightly floured work surface, roll the pastry out to a square the thickness of a £1 coin. Cut it into quarters, then put a stuffed mushroom in the centre of 2 of the squares. Brush a little water around each mushroom, then lay a second pastry square on top, pressing down around the filling to remove all the air (see tip). Trim the pastry into circles, leaving a 2-3cm border around the filling. Using a floured fork, press all around the border to seal. Brush the pastry with beaten egg, then lightly score the top with curved lines. Chill for 10 minutes.
7. Brush the pithiviers again with beaten egg, bake in the top third of the oven for 20-25 minutes, on an oiled baking sheet, until puffed and golden. Serve with the green beans, drizzled with a little olive oil.