Season 1½ lbs lean stew meat with Kosher salt, Worcestershire flavored ground pepper and granulated garlic. Vacuum pack with a couple pats of butter. Omit if your beef is fatty enough.
Sous-vide for 24+ hours at 140°
Cut carrots, onions and celery (seasoning is optional*) and cook until tender in beef broth. At this point add leftover 'au jus' from previous steak, hamburger or roast cooks. Add the stew beef and any juices that are in the bag. If needed, add more beef broth, or V-8 vegetable juice, to cover the meat and vegetables. Cover and simmer for a couple of hours. Cool and refrigerate.
On medium heat, bring stew to temperature, add potatoes, cook for 30 minutes, simmer for a couple more hours and then serve. Thickening with cornstarch and water is optional.
*if using au jus from previous cooks, you may not need to seasoning the vegetables with salt.