2. Pour 150ml boiling water over the dried Porcini mushrooms and leave them to soak for 15 minutes. Then strain through a fine sieve and reserve the liquid as it passes through.
3. Heat the oil in a large casserole dish and fry the pork fillet for 5–6 minutes until lightly browned.
4. Add the onion, garlic, chestnut mushrooms and Porcini mushrooms. Cook in a pan for 1–2 minutes until the onion starts to soften.
5. Add the wine, cream and half the sage and bring to the boil.
6. Cover the casserole with a lid and place in the oven. Cook for 40–45 minutes or until the pork is completely cooked through with no pink juices. If the casserole starts to dry out before the pork is cooked, add the reserved mushroom water.
7. Season with freshly ground black pepper then sprinkle over the remaining sage to serve.