Prepare the Pot Roast:
Preheat your oven to 325°F (163°C).
Heat the vegetable oil in a large Dutch oven or oven-safe pot over medium-high heat.
Season the beef chuck roast with salt and pepper. Sear the roast in the hot oil until browned on all sides, about 4-5 minutes per side. Remove the roast and set aside.

In the same pot, add the diced onion and cook until softened, about 5 minutes. Add the minced garlic and cook for another minute.
Stir in the tomato paste and cook for 1-2 minutes.
Add the beef broth, red wine (or additional beef broth), dried thyme, dried rosemary, and bay leaf. Stir to combine.
Return the roast to the pot and add the carrots and celery.
Cook the Pot Roast:
Cover the pot with a lid and transfer it to the preheated oven.
Roast for 3-4 hours, or until the meat is tender and easily shreds with a fork. Check occasionally and add more broth if needed.
Make the Mashed Potatoes:
While the roast is cooking, place the peeled and cubed potatoes in a large pot. Cover with water and add a pinch of salt.
Bring to a boil and cook until the potatoes are tender, about 15-20 minutes.

Drain the potatoes and return them to the pot. Add the butter and milk, and mash until smooth and creamy. Season with salt and pepper to taste.
Serve:
Remove the pot roast from the oven and let it rest for a few minutes before slicing or shredding.
Serve the pot roast over a bed of mashed potatoes, spooning some of the gravy and vegetables from the pot over the top.
Prep Time: 20 minutes | Cook Time: 4 hours | Total Time: 4 hours 20 minutes | Servings: 6-8 | Calories: Approximately 500 kcal per serving