Melt butter in a large pot, then sauté onions and mushrooms over medium heat until onions are soft and translucent, about 15 minutes. Add 4 cups water, wine, soy sauce, paprika, dill, and thyme. Bring to a simmer and cook until the liquid is reduced by half.

In a small bowl, whisk flour into milk until smooth. Add to the soup and simmer until the soup begins to thicken, about 10 more minutes.

Over low heat, slowly stir in sour cream and lemon juice until completely combined. Serve hot with a dollop of sour cream.

Preheat oven to 425 degrees Fahrenheit.

Mix oil, basil, parsley, garlic, thyme, oregano, black pepper, salt, red pepper, and lemon juice in a bowl. Spread over sliced baguettes and bake for 10 to 15 minutes. Serve with hot soup.