Preheat a large heavy pot or Dutch oven over medium-high heat.
Season the beef generously with salt and pepper.
Sear the beef on all sides until browned, about 3-4 minutes per side. Remove the beef and set aside.
In the same pot, add onions and garlic. Sauté until softened and fragrant, about 2-3 minutes.
Add the red wine to deglaze the pot, scraping up any browned bits from the bottom.
Return the beef to the pot and add the beef broth, carrots, parsnips, and fresh thyme.
Bring the mixture to a simmer, then reduce the heat to low, cover, and let it braise slowly for about 1.5 to 2 hours, or until the beef is tender.
Adjust seasoning with additional salt and pepper if necessary.
Serve hot, enjoying the tender beef and flavorful root vegetables in a rich red wine sauce.