Heat the olive oil in a large pot or Dutch oven over medium heat. Add the mushrooms and sauté for 5 minutes, or until the mushrooms have softened and released their liquid.
Add the garlic, thyme, red chili flakes, salt, and pepper and continue to cook for another minute.
Add the cubed potatoes and vegetable stock to the pot. Bring to a boil, then reduce heat and simmer for 20 minutes or until the potatoes are tender.
Take out a ladle of liquid and mix it with the milk to temper it, then add the mixture to the pot. Do the same with the heavy cream.
Stir in the freshly grated Parmesan and fresh parsley.
Adjust the seasoning to taste and serve warm, sprinkled with extra fresh parsley and grated Parmesan if you like.
