Heat the olive oil in a Dutch oven over medium heat. Season the lamb with salt and pepper, then brown it in batches until all sides are seared. Remove the lamb and set it aside.
Add the onion to the same pot and cook until it softens. Stir in the garlic and cook for one minute more.
Pour in the Bordeaux wine and scrape the bottom of the pot to release any browned bits.
Return the lamb to the pot along with the beef broth. Add the carrots, parsnips, potatoes, and thyme sprigs. Bring the mixture to a gentle simmer.
Cover the pot and cook on low heat for about two hours, stirring occasionally, until the lamb is tender and the vegetables are soft.
Remove the thyme sprigs. Taste and adjust salt and pepper if needed before serving.