This is based on a recipe from Mary McCartney’s book ‘At my Table’ it’s a great book and she cooks in a way that’s very similar to me, in fact this is similar to the cashew nut and mushroom pie that is a favourite in my family. This pie makes a great centerpiece for a roast dinner or festive feast.
I started by frying a large red onion in olive oil and after a couple of minutes added 500g of chopped mushrooms (I used eryngii & shimeji, the original recipe suggests chestnut mushrooms ) and 4 cloves of crushed garlic. Next I added 200g cooked chestnuts, 1 tbsp of mushroom (light) soy sauce, 1tsp of dark soy sauce, 1 tsp of balsamic vinegar, 1 tbsp of herbs de Provence and a couple of crushed bay leaves. I covered the sauce pan and cooked them for a few minutes. Then I added a small handful of crushed porcini mushrooms, a heaped tsp of whole grain mustard and then stirred in a tbsp of cornflour. Then I added 200ml of water and simmered the for about 5 mins it should thicken into a rich gravy. Then I allowed the mixture to cool.
Then I heated my oven to 200 degrees C / 400 F. I rolled out about 350g of puff pastry dusting it with whole meal flour. I rolled it into a square of about 30cms and pricked it with a fork and used it to line a 20cm pie dish. I then put the mushroom filling in the middle and folded the corners in, painting each with a beaten egg. I then baked it for about 35 mins until golden brown.