Spray slow cooker with nonstick cooking spray and place steak in the bottom. Top with salt, pepper, parsley, garlic powder and onion powder then mix to evenly distribute spices.
Add mushrooms, 1 cup beef broth and Worcestershire sauce to the slow cooker. Cover and cook on low for 5-6 hours or high for 2-3 hours.
Whisk remaining 1⁄2 cup broth with cornstarch to make a slurry then add to slow cooker and stir to combine. Cover and cook on high for 20 minutes.
Stir in yogurt and cook for an additional 10 minutes. Meanwhile, cook noodles according to package directions, then drain and mix into sauce in the slow cooker and serve.