Wash, clean, and roughly chop the mushrooms.
Heat olive oil in a saucepan. Add finely chopped garlic, onion, thyme, and saute for a minute to release the aroma and infuse the flavor in the oil.
Add chopped mushrooms, and season with salt. Saute till mushrooms are caramelized and all the liquid is evaporated. Remove half of the sauteed mushrooms.
Blend the removed mushrooms to a smooth puree or paste. Set aside.
Add vegetable stock to the remaining mushrooms, stir to combine, and close the lid of the pan. Cook mushrooms for 5 - 6 minutes over medium heat to soften a bit.
Open the lid, add milk, mushroom puree, and pepper. Stir to mix, and simmer the soup for 3 - 5 minutes.
Garnish soup with chopped parsley.
Serve healthy mushroom soup warm with toasted bread slices.