20-30 minutes before you’d like to begin preparing your pot roast, transfer the beef chuck roast from the refrigerator to the kitchen counter, allow it to come to room temperature. When you’re ready to begin preparing your pot roast, preheat the oven to 325 degrees F, situating a rack in the center of the oven. Gather & prep all ingredients according to ingredients list.
Add olive oil to a large, heavy-bottomed oven-safe pot with a tight fitting lid over medium-high heat. Pat the surface of the beef chuck roast as dry as possible. Generously season with S&P. Spread flour out on a large plate, then place the beef chuck roast over top, pressing to lightly coat the surface of the roast in flour. Shake off excess. Once oil in the pot is shimmering hot, add in the seasoned dredged roast. Cook 3-4 minutes per side, including the ends & narrow sides, until nicely browned. Transfer to a plate & set aside.
To the same pot used to brown the chuck roast, add in the baby potatoes, carrots, yellow onions, garlic, beef stock, Worcestershire sauce, & onion soup mix. Stir to combine. Use a wooden spoon to push the vegetables to the sides of the pot, then nestle the browned chuck roast in the center. Bring the pot roast to a simmer.
Cover the Dutch oven & carefully transfer the pot roast to the preheated oven to braise for 3 – 3 1/2 hours, until the chuck roast is fork-tender (i.e. it shreds very easily with a fork).
Once the beef is tender, remove the pot from the oven. Carefully transfer to a serving platter & set aside. Place the Dutch oven back on the stovetop over medium heat. Measure beef stock in a liquid measuring cup, warming it in the microwave for 30 seconds to 1 minute. Whisk in the flour. Once combined, add it to the Dutch oven – whisking constantly, stir in the flour slurry. Simmer, stirring occasionally, for 3-4 minutes until thickened as desired. Taste and season with additional S&P as needed.