First, place the dried porcini mushrooms in a small bowl and cover with 200ml of boiling water. Let them soak for at least 20 minutes while you prepare the other ingredients.

In a large stockpot or Dutch oven, heat the olive oil and butter over a medium heat. Add the chopped onion, carrots, and celery. Sauté for 8-10 minutes, stirring occasionally, until the vegetables have softened and the onion is translucent.

Add the minced garlic and cook for another minute until fragrant. Now, turn up the heat slightly, add the sliced chestnut mushrooms and the thyme sprigs. Cook for 10-12 minutes, stirring infrequently, until the mushrooms have released their liquid and have started to brown nicely. What works best for me is cooking the mushrooms in two batches to ensure they get properly browned and don't just steam.

Once the porcini mushrooms are rehydrated, lift them out of the soaking liquid (reserving the liquid), chop them finely, and add them to the pot. Pour in the reserved soaking liquid, being careful to leave any grit at the bottom of the bowl. Stir everything together and cook for 2 minutes.

Pour in the vegetable stock and add the rinsed wild rice. Bring the soup to a boil, then reduce the heat to low, cover the pot, and let it simmer gently for 45-50 minutes, or until the wild rice is tender and has started to split.

Once the rice is cooked, remove the thyme sprigs. Stir in the double cream and the chopped fresh parsley. Let the soup warm through for a couple of minutes, but do not let it boil.

Season generously with sea salt and freshly ground black pepper to your taste. Serve hot with a sprinkle of extra parsley.