Method

• 1.
  Melt 20g butter with the olive oil in a heavy-based saucepan over high heat for 2-3 minutes until foaming. Add eschalot, garlic and thyme, and cook, stirring, for 1-2 minutes until softened. Add the stock and bring to the boil, then add the porcini. Reduce heat to low and simmer for 5 minutes or until mushrooms are plump and rehydrated. Strain through a fine sieve into a bowl, reserving solids.
• 2.
  Return stock to saucepan and bring to the boil over high heat. Add the pasta and cook for 9 minutes or until al dente. Strain, reserving stock.

• 3.
  Meanwhile, melt remaining 30g butter in a large saucepan over high heat. In two batches, cook mushrooms, tossing, for 4 minutes or until golden and softened.
• 4.
  Return reserved mushroom and onion mixture and 1L (4 cups) reserved stock to pan. Bring to the boil over high heat and boil for 6 minutes or until reduced and thickened. Add pasta and cook, tossing, for a further 2 minutes or until sauce thickly coats the pasta. Fold through parsley and serve topped with parmesan.