Preheat your oven to 375°F.
Season the lean beef stew meat with salt, pepper, and finely chopped rosemary.
In a heavy, oven-safe pot or Dutch oven, sear the beef on all sides over medium-high heat until browned. Transfer the beef to a slow cooker if desired, or continue in the pot.
Peel and cut the carrot, parsnip, and beetroot into uniformly sized chunks.
In a bowl, toss the prepared root vegetables with olive oil, salt, and pepper.
If using the oven-safe pot, add the vegetables around the beef, cover with a lid, and place in the oven. If using a slow cooker, layer the vegetables on top of the beef.
Cook on low heat for about 3 hours in the slow cooker or in the oven for 2.5 to 3 hours until the beef is tender and the vegetables are roasted and caramelized.
Once cooked, stir gently to combine the flavors and serve warm.