Melt the butter in a dutch oven over medium heat, then add olive oil. Sauté onions and shallots for 6 minutes.
Add cremini mushrooms and cook for 3 minutes. Add thyme, dill, and smoked paprika and cook for 1 minute.
Add white wine and cook until liquid has reduced by about half. Add soy sauce and vegetable broth and bring to a boil. Lower heat to a simmer and cook for 15 minutes.
In a small bowl, add milk and flour and whisk until well combined. Pour into soup and stir to combine. Cook for another 15 minutes, stir every few minutes.
Add salt, pepper, lemon juice, parsley and crème fraîche. Stir to combine.
Ladle into bowls and serve.