Trim roast of excess fat, cut into 1" cubes. Allow to come up to room temperature.
Pat beef cubes dry with a paper towel, season well with salt and pepper.
Measure about 1 tablespoon of the olive oil into a large, heavy bottomed pot. Heat over high heat.
Working in batches - and allowing space between each piece - brown the beef in the heated oil.
As beef is well browned on each side, remove from the pan and continue with remaining beef pieces, using more oil if necessary.
Remove all beef from the pan.
Add a splash of the beef broth to the pan, scraping and stirring the beef drippings - this is called deglazing.
Once the beef is all scraped off the bottom of the pan and incorporated, add red wine vinegar and tomato paste, stir well to combine. Add remaining beef broth, bay leaves, and the beef.
Bring to a boil, then reduce heat to a low simmer. Simmer over low heat for 1 ½ hours, or until meat is very tender.
As the beef cooks, prepare your vegetables: Quarter or slice the mushrooms, chop the onion, peel and slice the carrot, chop the celery, press or mince the garlic, peel and chop the celery root and turnips,
Add all of the vegetables except the Brussels sprouts, stir to combine.
Bring it to a boil again, then turn heat back down to low and simmer for another 30 minutes or so. Add Brussels sprouts, continue simmering another 10 minutes, or until the vegetables are tender.
In a small bowl, combine the dried parsley, gelatin, xanthan gum, dried thyme, and dried rosemary. Be sure to stir well - you want the xanthan gum well distributed over the other ingredients, to prevent clumping.
Add herb mixture to the pot, stir well to combine. Allow stew to simmer for a few minutes to thicken.
Taste, season with salt and pepper, and serve.