Make sure you take the rump roast out of the refrigerator at least one hour before you plan to start cooking it. You want to get the meat as close to room temperature as possible.
15 minutes before you plan to put the roast in the oven preheat your oven to 450°F and get your roasting vegetables prepped by cutting them up, season with salt & pepper and combine in a big bowl. Add some olive oil and give them a stir with a spoon or your hands if you like that sort of thing.
Remove the roast from its packaging. I suggest you do this over the sink to avoid any unnecessary mess from the juices. Pat the rump roast dry with paper towels and generously season with salt & pepper. Some people like to make a bunch of slits in the meat and place slivers of garlic into each cut. Great idea, one I'll try next time. Place the roast fatty side up on a roasting pan large enough to hold the beef and vegetables. If you don't have a pan big enough, use two separate pans. I have seen some people suggest putting the roast directly on the oven rack with a pan underneath to catch the drippings.Another great idea allowing the oven's hot air to circulate around the meat eliminating the need to rotate the roast while cooking. I don't want to have to clean the oven rack so I use a pan.
Add the vegetables to the pan and stick a meat thermometer into the end of the roast, right in the middle.
Add the sprigs of fresh rosemary on and around the meat. Place the roasting pan into the oven on a lower rack and roast at 450°F for 20 minutes to brown the meat.
Reduce the heat to 300°F and continue cooking until the meat reaches the desired temperature and the vegetables are cooked.How long this takes will vary depending on the size of your roast, the type of oven you have, the amount of vegetables you're preparing and several more factors. Some people will tell you 20 minutes per pound, others 10 minutes per pound. I suggest you estimate somewhere between the two but use a meat thermometer and keep your eye on it. If the meat is done but the vegetables are not, remove the meat and transfer to a cutting board and place the vegetables back into the oven. Loosely cover the roast with some aluminum foil while it rests for 5 to 10 minutes.If the vegetables are done but the meat has not yet reached its desired temperature, transfer the vegetables to a bowl, cover with foil or clear wrap and return the roasting pan back into the oven.
When the meat is done and rested and the vegetables are ready to go, thinly slice the beef and serve with a plateful of roasted vegetables.