Preheat your oven to 325°F (163°C).
Season the beef roast generously with salt and pepper.
In a large Dutch oven, heat olive oil over medium-high heat.
Sear the beef roast on all sides until browned, about 4-5 minutes per side.
Remove the beef roast and set aside. In the same pot, add chopped onion and garlic.
Cook until the onion is translucent, about 5 minutes.
Add crushed tomatoes, beef broth, balsamic vinegar, oregano, and red pepper flakes. Stir well.
Return the seared roast to the pot, spooning some sauce over the top.
Cover the pot with a lid and place it in the preheated oven.
Roast the beef for about 3 to 4 hours, or until it is fork-tender.
Once cooked, remove the pot from the oven and let it rest for 15-20 minutes before serving.
Slice the roast and serve with the sauce ladled over it, garnished with fresh basil.