Heat olive oil in a large Dutch oven or oven-safe pan over medium-high heat.
Add the beef roast, searing it on all sides until browned (about 4-5 minutes per side).
Remove the beef and set aside.
In the same pan, cook the sliced onion until soft (about 5 minutes).
Stir in tomato paste, minced garlic, thyme, rosemary, and red pepper flakes (if using). Cook for 1 minute until fragrant.
Add beef broth, cranberry sauce (optional), soy sauce, maple syrup, and Worcestershire sauce to the pan. Stir well to combine.
Return the seared beef to the pan. Add cranberries and carrots, ensuring the roast is partially submerged in the liquid.
Preheat your oven to 275°F. Cover the pan with a lid and transfer it to the oven.
Let the beef braise for 3-4 hours, or until tender and easily shredded with a fork.
Simmer on low heat for 3-4 hours.
Cook on LOW for 8-10 hours or HIGH for 4-6 hours.
Remove the beef from the pan. Skim any excess fat from the surface of the sauce.
For a thicker sauce, bring the liquid to a simmer and stir in a cornstarch-water slurry. Simmer until the sauce thickens.
Slice or shred the beef. Serve with braised carrots and cranberries, drizzling the sauce over the top for added flavor.
