Start by heating a tablespoon of olive oil in a large skillet over medium-high heat. Sear the beef chunks until they're browned on all sides, about 5-7 minutes, then transfer to the slow cooker or set aside.
Reduce the heat in the skillet to medium, add the remaining oil, and sauté the diced onion until it turns translucent and fragrant, about 3-4 minutes. Add the minced garlic and cook for another minute until aromatic.
Pour the cooked onion and garlic mixture into the slow cooker with the browned beef chunks. Add the sliced sunchokes, chopped parsnips, and cubed beets.
Pour in the beef broth, ensuring the ingredients are mostly covered. Stir in fresh thyme and season with salt and pepper to your taste.
Cover the slow cooker and set it to low. Let the stew simmer gently for 3 to 4 hours, or until the beef is tender and the vegetables are cooked through but still retain some crunch.
Once cooking is complete, remove the lid and give the stew a gentle stir. Taste and adjust the seasoning with additional salt and pepper as needed.
Serve the stew hot, garnished with fresh herbs or a slice of crusty bread on the side for a comforting meal.
