Soupe aux champignons- Mushroom soup

I love fall: The change of leave colors, the pretty sweaters, the fun scarves, and the soups!! After a beautiful summer, we have been enjoying an Indian summer, and today it has "finally" cooled down! Which inspired me to make a mushroom soup!! Quick and easy, perfect for a "déjeuner du Lundi", a Monday lunch.

• 4 tablespoons unsalted butter
• 2 cups chopped onions
• 1 pound fresh mushrooms, sliced
• 1 tablespoon paprika
• 1 tablespoon soy sauce
• 2 cups chicken broth
• 1 cup milk
• 3 tablespoons all-purpose flour
• 1 teaspoon salt
• ground black pepper to taste
• 2 teaspoons lemon juice
• 1/4 cup chopped fresh parsley
• 1/2 cup sour cream
• Roasted chicken pieces