Preheat oven to 300°F.
Pat the beef dry with paper towels and season generously with salt and pepper. If using a whole chuck roast, cut it into approximately 1½ to 2-inch cubes.
Heat olive oil in a large Dutch oven over medium-high heat.
Working in batches, brown the beef on all sides, approximately 2–3 minutes per side. Transfer to a plate and set aside.
Don't worry about cooking the beef all the way through. You're just developing that beautiful browned crust that adds so much flavor.
Reduce heat to medium.
If using bacon, add it to the pot and cook until lightly browned. Add the diced onion and cook for approximately 5 minutes, until softened.
Add the garlic and cook for another 30 seconds.
Stir in the tomato paste and cook for 1–2 minutes.
Sprinkle in the flour and stir continuously for another minute.
Slowly pour in 6 cups of beef broth, stirring and scraping up all the browned bits from the bottom of the pot.
Add Worcestershire sauce, dried thyme, dried rosemary, and bay leaves.
Return the browned beef and any accumulated juices to the Dutch oven.
Bring everything to a gentle simmer on the stovetop.
Cover the Dutch oven with its lid and transfer to the oven.
Cook at 300°F for approximately 2 hours.
The beef will begin to become tender as it slowly braises in the broth.
Carefully remove the Dutch oven from the oven.
Add the carrots and potatoes, stirring gently to distribute them throughout the stew.
The liquid should surround most of the vegetables. Add additional beef broth if necessary.
Bring the stew back to a gentle simmer on the stovetop before returning it to the oven.
Cover and cook for another 60–90 minutes, or until the beef is fork-tender and the potatoes and carrots are cooked through.
Once the beef and vegetables are tender, remove the Dutch oven from the oven and place it on the stovetop.
If you have more broth than you'd like, carefully ladle some out and reserve it.
For a thicker gravy, mix 2 tablespoons cornstarch with 2 tablespoons cold water until smooth.
Bring the stew to a gentle simmer and slowly stir in the cornstarch mixture.
Let simmer for 2–3 minutes until thickened.
If needed, repeat with an additional tablespoon of cornstarch mixed with a tablespoon of cold water.
Remove the bay leaves.
Stir in balsamic vinegar and taste for seasoning, adding additional salt and pepper as needed.
Garnish with fresh parsley and serve warm with crusty bread.