Season the beef with salt and pepper.
Heat the oil in a skillet over medium high heat and sear the roast on all sides. Set aside.
Cook the bacon, garlic, and onion in the skillet for 4-5 minutes or until the onion is translucent and the bacon is cooked but not crispy. Set aside.
Deglaze the pan with 1/2 cup of the beef broth. Add the pan liquid to the crock pot. Add the rest of the beef broth to the crock pot.
Add the beef roast, bacon and onion mixture, and herbs to the crock pot. Set it to cook on high for 5 hours or on low for 8.
Add the turnip to the crock pot 1 hour before it is finished if on high, or 2 hours before if on low.
Drain the liquid from the crock pot into a saucepan. Simmer the liquid for about 10 minutes to reduce it and concentrate the flavors. While this is simmering, slice the roast and keep it warm.
Take the cooking liquid off the heat and thicken with UP TO 1/2 tsp of xanthan gum. Season the gravy, adjusting the salt and pepper as needed, and serve!