Pat the beef chuck roast dry with paper towels, cut into uniform cubes, and toss in seasoned flour mix of salt and black pepper.

In a skillet, heat vegetable oil over medium-high heat. Sear seasoned beef for 3-4 minutes per side until golden brown, then transfer to slow cooker.

In the same skillet, add chopped yellow onion and cook for 5-7 minutes until golden and softened, then add minced garlic and sauté for an additional minute.

Pour beef broth into the slow cooker with browned beef and sautéed onions. Add sliced mushrooms and dried thyme; stir gently to combine.

Cover slow cooker and set to HIGH. Cook for about 4 hours, until beef is tender.

Add wide egg noodles and dried parsley, then reduce slow cooker to LOW. Cook for an additional 30 minutes until noodles are al dente.

Let the dish rest for 5-10 minutes before serving in bowls, garnished with parsley.