To make your delicious Cranberry Balsamic Roast Beef, follow these step-by-step instructions:

1. Preheat Oven: Preheat your oven to 325°F (165°C).
2. Prepare the Roast: Season the beef roast generously with salt, pepper, rosemary, and thyme.
3. Sear the Meat: In a large oven-safe skillet, heat olive oil over medium-high heat. Sear the roast on all sides until browned (about 3-4 minutes each side).
4. Set Aside the Roast: Once browned, remove the roast from the skillet and set aside on a plate.
5. Sauté Onions and Garlic: In the same skillet, add chopped onion and minced garlic, sautéing until they become fragrant and translucent.
6. Mix Sauce Ingredients: In a bowl, combine the cranberry sauce and balsamic vinegar, mixing until smooth.
7. Deglaze: Pour the cranberry mixture into the skillet with the sautéed onions and garlic. Scrape the bottom to release any browned bits from the skillet.
8. Return the Roast: Place the beef roast back into the skillet, making sure to coat it with the sauce.
9. Bake in the Oven: Cover the skillet with a lid or aluminum foil and bake in the preheated oven for about 1 hour and 15-30 minutes or until the internal temperature reaches your desired level of doneness (145°F for medium-rare).
10. Rest the Meat: Once cooked, remove the roast from the oven and let it rest for 10-15 minutes before slicing. This allows the juices to redistribute for optimal tenderness.
11. Serve: Slice the roast against the grain and serve drizzled with the cranberry balsamic sauce from the skillet.