Season steaks with salt and pepper. Add to slow cooker along with garlic powder, onion, onion soup mix, and beef broth.
Set slow cooker to low for 8 hours.
1 hour before you’re ready to serve, mix cold water and cornstarch in a small bowl and stir into slow cooker. Cook on high until gravy has thickened, stirring periodically.
Serve over buttered egg noodles, and garnish with more pepper.