Melt butter in large pot over medium heat. Saute onions five minutes.
Add mushrooms and saute five more minutes.
Stir in dill weed, paprika, soy sauce, and chicken broth. Reduce heat to low. Cover and simmer 15 minutes.
In a separate bowl, whisk the milk and flour together. Pour into soup, stir to blend. Cover and simmer 15 minutes, stirring occasionally.
Stir in the salt, black pepper, lemon juice, parsley, and sour cream. Mix together and continue cooking over low heat another 3-5 minutes. DO NOT BOIL. Serve immediately.