Pick out a good handful of interesting looking mushrooms. Pat any mud away using a damp cloth. Cut the largest, denser mushrooms into four, and tear any particularly large floppy ones in two. But ultimately don’t alter their natural shape too much!
Put a large saucepan of water on to boil.
Place a large frying pan over a medium-high heat. Add the cooking oil and 10g truffle butter. When the butter has melted and is beginning to foam, place the mushrooms in the pan, in one layer if possible, with any cut sides facing down and with a pinch of flaky sea salt sprinkled over the top. Only turn the mushrooms when they begin to colour. Transfer into a spare bowl when golden and/or glistening. The different types will take different times, but all will be cooked in 3-4 mins. Scrape any cooking juices into the bowl too and add a squeeze of lemon juice.
Transfer the gnocchi into the now boiling water and cook for 2-3 mins, until they float to the surface. Drain, reserving the cooking water.
Return the frying pan to the hob over a medium-high heat. Add the remaining truffle butter and when it begins to foam (but before it browns), pour in 100ml gnocchi water. When that boils, shake and stir the pan so the butter and water emulsify. Add another 50ml gnocchi water, the pepper and thyme leaves, then the cooked gnocchi and mushrooms. Shuffle the pan, add the cheese and keep tossing the ingredients until you’ve a pan of gnocchi and mushrooms in a silky, cheesy, fragrant sauce, adding more cooking water if needed.