While the meatballs are cooking, prepare the sauce.
Make a roux by melting the butter in a large skillet. Add the flour to the butter and whisk well. Cook over medium-low heat, whisking often, until mixture is creamy and turns a dark golden brown.
4 tablespoons unsalted butter, ¼ cup all-purpose flour
Add beef broth, chicken broth, cream, sour cream, bouillon granules, soy sauce, Worcestershire sauce, Dijon mustard, cider vinegar, sugar, and black pepper. Taste, then season with salt, only if needed.
3 cups low-sodium beef broth, 3 cups low-sodium chicken broth, 2 cups heavy cream, ¾ cup sour cream, 1½ tablespoons low-sodium soy sauce, 2 teaspoons Worcestershire sauce, 1 teaspoon Dijon mustard, 2 teaspoons apple cider vinegar, 1 tablespoon granulated sugar, ½ teaspoon freshly ground black pepper, Salt, 1 teaspoon Beef instant bouillon granules
Bring to a boil over medium heat, and add the noodles. Restore the soup to a boil and reduce heat to low to simmer until noodles are al dente.
8 ounces egg noodles
Add the meatballs, and simmer, stirring gently & often, until noodles are cooked through and soup has reduced to desired consistency. (See recipe note.)
Add chopped parsley and stir gently.
2 tablespoons minced fresh parsley
Serve and garnish with dollops of Lingonberry jam, sour cream, and a sprinkle of additional chopped fresh parsley.
Lingonberry jam or cranberry sauce, Chopped fresh parsley, Sour cream