01 - Preheat your oven to 325°F.
02 - Pat the beef roast dry with paper towels 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 sliced onions and minced garlic. Sauté for 2-3 minutes until fragrant and softened.
05 - Add carrots, celery, and baby potatoes to the pot. Stir well to coat with the aromatic base.
06 - Return the roast to the pot, nestling it among the vegetables. Pour in beef broth, water, and Worcestershire sauce. Sprinkle with thyme, rosemary, and add bay leaves. Bring to a gentle simmer.
07 - Cover 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.
08 - Place peeled, cubed russet potatoes in a saucepan with salted water. Bring to a boil and cook until fork-tender, about 15-20 minutes. Drain thoroughly, mash with butter and milk until smooth, and season with salt and pepper to taste.
09 - Steam or boil fresh green beans until just tender-crisp, about 5 minutes. Drain well and toss with butter and garlic powder.
10 - Transfer the beef roast and vegetables to a serving platter. Discard the bay leaves from the cooking liquid.
11 - Skim excess fat from the pot juices. In a small bowl, whisk cornstarch with cold water until smooth to create a slurry. Bring the remaining pot juices to a simmer on the stovetop, whisk in the slurry, and cook for 2-3 minutes until thickened. Adjust seasoning as needed.
12 - Slice or shred the pot roast against the grain. Serve alongside braised vegetables, creamy mashed potatoes, seasoned green beans, and ladle hot gravy over the top.