01 - Preheat your oven to 325°F.
02 - Pat the beef roast dry and season generously with salt and pepper on all sides.
03 - Heat vegetable oil in a large Dutch oven over medium-high heat. Sear the roast on all sides until deeply browned, about 4-5 minutes per side. Remove and set aside.
04 - In the same pot, add onions and garlic. Sauté for 2-3 minutes until fragrant.
05 - Add carrots, celery, and baby potatoes to the pot. Stir to coat with the aromatics.
06 - Return the roast to the pot, nestling it among the vegetables. Pour in beef broth, water, and Worcestershire sauce. Sprinkle in thyme, rosemary, and add bay leaves. Bring to a simmer.
07 - Cover the pot with a tight-fitting lid and transfer to the oven. Braise for 2.5 to 3 hours, until the beef is fork-tender.
08 - Boil russet potatoes in salted water until fork-tender, about 15-20 minutes. Drain thoroughly, mash with butter and milk until smooth, and season with salt and pepper.
09 - Steam or boil green beans until just tender, about 5 minutes. Drain well, toss with butter and garlic powder.
10 - Once the roast is done, remove the beef and vegetables to a platter. Discard bay leaves.
11 - Skim excess fat from the pot juices. In a small bowl, whisk cornstarch with cold water to make a slurry. Bring the pot juices to a simmer on the stovetop, whisk in the slurry, and cook until thickened, 2-3 minutes. Taste and adjust seasoning.
12 - Slice or shred the pot roast. Serve with the braised vegetables, mashed potatoes, green beans, and gravy.