Brush the mushrooms clean, then slice them
Heat the butter/ olive oil in a large saucepan, add chopped onion, celery and cook for 2-3 minutes.
Add sliced mushrooms and thyme, cook them over slow medium heat till the edges of mushroom start to turn crisp.
Pour the vegetable stock into the pan along with macadamia nuts and bring to the boil, turn the heat down and add skim milk boil again and season it with salt and white pepper.
Allow the content of pan to cool down a bit and then in a blender jar blend everything to a smooth mixture.
Strain the soup and bring it to boil once again, check for the seasoning and adjust it according to your own taste.
Ladle the soup into bowls, garnish with sharp cheddar and serve it hot.