Start by preheating the oven to 350 degrees F.
Place the dutch oven on the stovetop over medium high heat. Add the oil and allow it to warm up. Pat the meat dry with a paper towel, season with salt and pepper, and sear all sides until browned.
Toss the onions into the same dutch oven and cook over medium heat until softened and edges turn amber. Stir occasionally, then add garlic and cook for about one minute.
Add a little broth to the dutch oven to deglaze the pan, scraping browned bits off the bottom with a wooden spoon.
Add the rest of the broth, Worcestershire sauce, and brown sugar to the pot and mix.
Add the seared pot roast back into the dutch oven.
Add the carrots and potatoes around the pot roast. Cover the pot and cook for about 2 ½ hours.
Remove the dutch oven from the oven, take off the lid, and cook for another 30 minutes.
Remove the roast and let it rest before slicing or shredding. Scoop out the veggies. Save the broth for gravy or thicken it with a slurry.
To make a slurry, mix 1 tablespoon of cornstarch with 1 tablespoon of water or broth and shake well. Pour into the pot and cook for about 20 minutes, stirring occasionally.