Preheat the oven: Start by preheating your oven to the appropriate temperature for your cut of beef. The recommended oven temperature can vary depending on the specific cut and desired doneness. As a general guideline, 325°F (163°C) is a common temperature for roasting beef.
Prepare the roasting bag: Take a large oven-safe roasting bag and place it in a roasting pan or baking dish. Make sure the bag is large enough to accommodate the beef roast comfortably.
Season the beef: Season the beef roast with salt, pepper, and any other desired herbs and spices. You can use a simple salt and pepper seasoning, or get creative with a blend of herbs like rosemary, thyme, garlic powder, or paprika.
Optional: Add vegetables: If you'd like to roast vegetables alongside the beef, chop them into chunks or wedges and place them in the roasting bag around the beef. Popular choices include carrots, potatoes, onions, and Brussels sprouts. Toss the vegetables with a bit of oil, salt, and pepper before adding them to the bag.
Place the beef in the roasting bag: Carefully place the seasoned beef roast into the roasting bag, ensuring it sits in the center. Close the bag securely with the provided tie or by using kitchen twine. Make a few small slits on the top of the bag to allow steam to escape.
Cooking time: Refer to a beef roasting chart or the instructions provided with your specific cut of beef to determine the appropriate cooking time. The cooking time can vary based on the size and thickness of the roast. As a rough guideline, plan for approximately 20 minutes of cooking time per pound of beef.
Resting and serving: Once the beef reaches the desired doneness, remove it from the oven and let it rest in the roasting bag for about 10-15 minutes. This resting period allows the juices to redistribute and the meat to become even more tender. Carefully open the bag, transfer the beef to a cutting board, and slice it against the grain. Serve with the roasted vegetables, if included.