Heat the oil in a large saucepan on medium heat. Add the finely chopped onion and soften for 4-5 minutes, stirring regularly and reducing the heat if starting to colour. Season with salt and black pepper.
Once the onion has started to turn soft and translucent, add the chopped garlic and cook for another 1-2 minutes.
Next, add the mushrooms and cook for 5-6 minutes or until softened. The mushrooms will release some water as they cook down, so it may help to increase the heat here.
Once the mushrooms are soft, add the white wine, thyme, sage, white pepper, nutmeg, and white miso paste. Stir well and cook for a couple of minutes to reduce the liquid.
Next, add the vegan stock and cashew cream (or other plant-based cream of your choice). Bring to a simmer and then cook on a low heat for 5-10 minutes.
In a jug or mug, combine the cornflour with a similar amount of cold water to create a slurry. Mix well to remove any lumps, then stir this into the soup and cook for a few minutes to thicken. Repeat this step for a thicker soup, or add a little extra stock to thin it out.
Adjust the seasoning and stir well before serving with fresh parsley and crusty bread.