Place ghee and olive oil in a stockpot over medium heat. Add onion and cook until it begins to brown (about 4 minutes)
Stir in garlic and cook for 1 minute. Add mushrooms, 2 Tablespoons thyme, and 1/2 tsp salt. Cook until mushrooms become limp (about 2-4 minutes) Add a thickener of rice flour or spelt flour for Blood Types B and AB if you like thick soup.
Add broth. Bring to a boil and, reduce to simmer for about 10 minutes.
Remove from heat. Transfer 1/2 the soup to a blender or separate bowl. You can blend our use a stick blender to make into bits in the pot.
Stir in the milk and sherry. Serve with a pinch of remaining thyme.
