In a large skillet, heat oil over medium heat.
Add the cubed beef to the skillet, seasoning with salt and pepper.
Once browned, transfer the beef to a slow cooker and add onions to the same skillet.
Sauté onions in the skillet until golden and caramelized, about 15 minutes.
Stir in the garlic and cook for 1-2 minutes until fragrant.
Pour in the beef broth and balsamic vinegar, scraping up any browned bits.
Transfer the mixture to the slow cooker with the beef and add thyme.
Cover and cook on low for 6-8 hours, or on high for 3-4 hours.
About 30 minutes before serving, cook the egg noodles according to package instructions.
Shred the beef in the slow cooker and stir in the cooked noodles.
Taste and adjust seasoning, serving hot garnished with fresh thyme if desired.
