Method

• 1.
  Preheat the oven to 180°C. Prick potatoes all over with a skewer, then place on a baking tray and roast for 1 1/2 hours or until tender. Cool slightly, then peel.
• 2.
  Pass potato through a potato ricer (or mash until smooth, then pass through a sieve) and season. Turn out onto a work surface, then make a well in the centre and add yolk. Gradually sprinkle over the flour and use your hands or a pastry scraper to incorporate it to form a soft dough. Divide into 4, cover with a tea towel and rest for 10 minutes.
• 3.
  Meanwhile, soak porcini in 1/4 cup (60ml) boiling water for 10 minutes. Place cream, lemon zest and 1/2 cup (125ml) water in a large saucepan. Bring to a simmer over medium heat, then remove from heat and set aside for flavours to infuse.

• 4.
  Heat oil and 30g butter in a frypan over medium-high heat. Cook mushrooms, in batches, for 2-3 minutes until golden (don't overcrowd the pan or they will stew). Return all mushrooms to the pan with thyme, parsley, porcini and soaking liquid. Cook for 1 minute or until the liquid has evaporated. Drizzle over the truffle oil and keep warm.
• 5.
  Reheat cream sauce over low heat for 2-3 minutes or until warmed through. Whisk in the remaining 30g butter, then add the lemon juice. Roll each dough portion into a long sausage on a lightly floured work surface, then cut into 2cm pieces. Bring a large saucepan of salted water to the boil and cook gnocchi, in batches, for 2-3 minutes until they rise to the surface. Remove with a slotted spoon and immediately place in a bowl of iced water. Drain the gnocchi, then gently stir through the cream sauce. Serve with mushrooms and micro herbs, if using.