Place the thawed cubed beef, sliced mushrooms, and minced garlic in a 6-quart or larger slow cooker.
Whisk together the broth, optional wine, Worcestershire sauce, Dijon mustard, garlic powder, onion powder, dried parsley, thyme, and flour. Pour over the beef and mushrooms, add the bay leaf, and stir.
Cover and cook on LOW for 8–10 hours, checking at eight hours. The beef should be fork-tender but should still retain recognizable pieces.
About 20 minutes before serving, add the softened cream cheese and cover for 10 minutes. Stir until smooth, add the room-temperature sour cream, cover, and heat on LOW for several more minutes without allowing the sauce to boil vigorously.
Meanwhile, cook and drain the egg noodles according to their package directions. Remove the bay leaf, season the stroganoff with salt and pepper to taste, and serve it over the hot noodles.