Bread, wine and cheese
You'll need a 2L capacity, 23cm x 30cm (9in x 12in) gratin dish. Preheat the oven to 220°C, 425°F, Gas 7. Place a frying pan on a high heat and add the butter. Add the lardons of bacon and cook them for 6-8 minutes until they are golden. Lift the bacon lardons out, leaving any fat in the pan, and set them aside. Tip the sliced wild or button mushrooms, whichever you're using, into the pan and season them with salt and freshly ground black pepper. Cook them for five minutes until they are soft and golden.
Mix the grated Cheddar cheese and the Dijon mustard and spread the mixture over the base of the gratin dish. Break the stale white yeast bread or stale sourdough bread, whichever you're using, into big chunks, about 4cm (2in) in size, and spread them over the cheese and mustard mixture in the gratin dish.
Drizzle the dry white wine over the top and place the dish in the preheated oven. Cook for 10-15 minutes, until the bread is slightly golden around the edges. Take it out of the oven, and add the lardons and the mushrooms.
Cut the semi-soft or soft cheese, whichever you're using, with all its rind, into wedges about 2cm (1in) wide at their widest and arrange them on top of the mushrooms, then scatter over the thyme. The dish can be prepared ahead up to this point. Put it back in the oven and cook it again for another 10-15 minutes until it is golden and bubbling.