Poland's regal wild mushroom soup: intensely fragrant dried porcini mushrooms (borowiki) and fresh mushrooms simmered in root vegetable broth, finished with sour cream and egg noodles.
Rinse the dried porcini mushrooms quickly, then place in a bowl and cover with 300ml hot water. Let steep for 25 minutes until plump. Lift out mushrooms and slice thinly, straining the steeping liquid through a fine sieve into the soup pot.
Melt butter in a soup pot over medium heat. Sauté the diced onion, diced root vegetables, and sliced fresh mushrooms for 7 minutes until fragrant and lightly golden.
Add the sliced porcini, strained mushroom liquor, and vegetable stock to the pot. Bring to a gentle boil, reduce heat, and simmer for 25 minutes until all vegetables are completely tender.
Whisk the flour into the sour cream with two ladles of hot broth to temper, then stir back into the soup, simmering gently for 2 minutes until velvety. Ladle over bowls of cooked egg noodles, scatter with fresh parsley, and serve.