In a heavy pot or Dutch oven, cook the onions and mushrooms in butter over medium heat until onions are soft and translucent, about 15 minutes.
Add the dill, thyme, paprika, chicken or vegetable stock, soy sauce and white wine. Bring the soup to a simmer and cook until the liquid reduces by half.
Meanwhile, in a small bowl, whisk the flour into the milk until smooth. Add the flour-milk mixture to the soup and cook until the soup begins to thicken, about 10 more minutes.
Turn the heat down to low and slowly stir in the sour cream and lemon juice.
Garnish the soup with parsley and serve hot.
**Yields 5 cups of soup. If you want to serve it to four people as a main dish, we recommend doubling the recipe.
