The USDA recommends cooking any beef to a minimum temperature of 140 degrees Fahrenheit to kill food-borne bacteria, which can multiply rapidly at warm temperatures below this point. However, some beef enthusiasts think this is too much and that 130 degrees Fahrenheit is best for medium-rare beef. A bottom round roast, also sometimes marketed as a rump roast, is ideal for medium-rare cooking because it can turn dry and chewy when overdone. With careful monitoring of the internal temperature, however, you can create a tender, juicy roast.
Prepare your roast a day ahead by applying your favorite paste for seasoning. Make sure the beef is dry enough to hold the paste; use a paper towel to blot any excess moisture first, if necessary. Cover the beef evenly with the paste, seal it in plastic wrap and refrigerate it overnight. Remove it from the refrigerator a few hours before cooking, and allow it to come up to room temperature.
Preheat your oven to 475 degrees F. Move your bottom round to a roasting pan, and place a meat thermometer into the thickest part of the beef.
Roast your bottom round at 475 degrees F for 30 minutes. Then, reduce the heat to 350 degrees F and continue roasting. Monitor the meat thermometer for your desired cooking level. Anything below an internal temperature of 130 degrees F is rare. Do not roast to an internal temperature of more than 140 degrees F or your roast will be medium, not medium rare.
Remove your bottom round roast from the oven to a carving platter when it has reached your desired temperature. Let it rest for 15 minutes before slicing and serving. Surface juices will reabsorb into the meat.