Season the beef chuck roast evenly with salt and black pepper on all sides.
Heat olive oil in a large skillet over medium-high heat. Sear the roast for 4-5 minutes on each side until browned. Transfer the roast to the slow cooker.
Add diced onion, minced garlic, and sliced mushrooms to the skillet and sauté for 4-5 minutes until softened. Transfer the mixture to the slow cooker on top of the roast.
Pour beef broth and Worcestershire sauce over the roast and vegetables in the slow cooker. Sprinkle smoked paprika and dried thyme evenly over the top.
Cover and cook on low for 8 hours, or until the beef is very tender and easily shredded with a fork.
About 30 minutes before serving, cook egg noodles according to package instructions. Drain and set aside.
Remove the roast from the slow cooker and shred it with two forks. Return the shredded beef to the slow cooker.
In a small bowl, whisk together sour cream and all-purpose flour until smooth. Stir this mixture into the slow cooker and cook on high for 20-30 minutes until the sauce thickens.
Serve the stroganoff over the cooked egg noodles and garnish with chopped fresh parsley.