Heat oil in a large pot, sauté the diced onion for 3-4 minutes. Add the crushed garlic and chopped thyme. Stir for an additional 3 minutes.
Add the sliced mushrooms and sauté for 5-8 minutes until softened and cooked through.
Add the flour, stir and cook for 3-4 minutes.
Pour in the vegetable stock, stir and bring to a boil. Reduce heat to a simmer and cook for 10 minutes.
Remove ½ of the soup and blend in a blender until smooth. Return the blended soup to the pot, add the milk and seasonings, stir through and bring to a simmer.
Taste the soup for seasoning. Add more salt if needed. Top with one tablespoon of chopped parsley.
Serve with a sprinkling of cracked pepper.
