Put the dried mushrooms in a jug and cover with 150ml just-boiled water. Set aside while you cook the fresh mushrooms. Cut or tear the mushrooms in half or into quarters, so they’re all a similar size, leaving any small ones whole.

Heat a large frying pan over a medium-high heat. Once hot, add a layer of mushrooms. Cook for 5-6 minutes, stirring halfway through, until the mushrooms are turning golden and starting to squeak. Tip onto a plate and repeat in batches until they are all cooked. Add a splash of the stock to the pan and bubble over a medium heat to scrape up the fond from the base of the pan, then tip this onto the mushrooms.

Return the pan to a medium heat and add the Mellow Yellow oil. Add the onion with the bay leaf and a pinch of salt and cook for 8-10 minutes, until softened. Stir in the garlic then season with a big pinch of salt and freshly ground black pepper. Stir in the flour and cook for a few minutes. Pour in the wine and allow to bubble for a few minutes.

Drain the dried mushrooms, catching the liquid, then stir this into the onion mixture, followed by the stock, marmite and mustard. Simmer for about 10 minutes, until reduced and thickened. Stir through the creme fraiche then remove the bay leaf.

Chop the dried mushrooms then add to the pan with the cooked mushrooms, stirring until all coated in sauce. Pour the mushroom mixture into a roasting tin or container to cool (spreading it out will cool it faster).

While the filling cools, make the pastry. Stir together the flour, salt and thyme in a bowl. Add the oil, mixing as you pour, until the flour is evenly coated. Add about 60ml cold water, a little at a time, until the mixture comes together as a smooth dough.

Roll out two-thirds of the dough between two sheets of baking paper to a 3-4mm-thick disc about 30cm in diameter. Use the pastry disc to line a 23cm pie tin then trim the edges, leaving an overhang all the way around. The pie crust is quite crumbly but will patch easily, so push some of the trimmings into any cracks. Roll out the remaining pastry dough to a smaller disc of similar thickness, large enough to form the lid of the pie with similar overhang. Lay this pastry on a baking tray and put the pastry dough lid, base and the cooled mushroom filling in the fridge to chill for 20 minutes.

Heat the oven to 200°C fan/gas 7. Stir the crumbled blue cheese into the chilled pie filling, then spoon it into the pastry dough base. Brush the overhang of the dough with a little milk then lay over the top disc of pastry. Press the pastry together all the way around the edge then use a fork to crimp and seal it. Use a small sharp knife to pierce a cross in the middle of the pastry lid. Brush the pastry with milk.

Slide the pie onto a baking tray and bake for 1 hour – 1 hour 15 minutes, until golden and crisp. Leave to rest for 15 minutes before slicing and serving. Enjoy the pie with mash and greens or a bitter leaf salad.