01 - Preheat your oven to 325°F.
02 - Pat the beef roast dry with paper towels and season generously with kosher salt and freshly ground black pepper on all sides.
03 - Heat vegetable oil in a large Dutch oven over medium-high heat. Sear the roast on all sides until well browned, about 4-5 minutes per side. Remove roast and set aside on a plate.
04 - In the same pot, add sliced onions and minced garlic. Sauté for 2-3 minutes until fragrant and translucent.
05 - Add carrots, celery, and baby potatoes to the pot. Stir well to coat with the aromatic base.
06 - Return the seared roast to the Dutch oven, nestling it among the vegetables.
07 - Pour in beef broth, water, and Worcestershire sauce. Sprinkle dried thyme, rosemary, and add bay leaves. Bring the mixture to a gentle simmer.
08 - Cover the pot with a tight-fitting lid and transfer to the preheated oven. Braise for 2.5 to 3 hours, until the beef is fork-tender and easily pulls apart.
09 - While roast braises, place russet potatoes in a large saucepan with salted water. Bring to a boil and cook until fork-tender, about 15-20 minutes. Drain well and return to the pot. Mash with butter and whole milk until smooth and creamy. Season with salt and pepper to taste.
10 - Steam or boil fresh green beans until just tender-crisp, about 5 minutes. Drain thoroughly, then toss with butter and garlic powder until well coated.
11 - Once the roast is done, carefully transfer the beef and vegetables to a serving platter. Discard the bay leaves.
12 - Skim excess fat from the cooking juices. In a small bowl, whisk cornstarch with cold water until smooth to create a slurry. Bring the pot juices to a simmer on the stovetop over medium heat. Whisk in the cornstarch slurry and cook for 2-3 minutes until thickened. Taste and adjust seasoning as needed.
13 - Slice or shred the pot roast against the grain. Serve immediately with braised vegetables, creamy mashed potatoes, seasoned green beans, and rich gravy ladled over the top.