One of the leanest cuts of beef, a center cut sirloin roast comes from the upper hindquarters. Even without the heavy fat marbling of other beef cuts, this roast becomes flavorful and tender if you lock in the natural moisture and cook it with low heat. Perhaps the easiest cooking method is a long roast in a slow cooker with water or broth. Braising and roasting are other recommended cooking methods for a center cut sirloin roast.
Allow the meat to warm to room temperature prior to cooking it. Set it on the counter under cover for 1 to 2 hours, depending on size.
Pour enough oil in a Dutch oven or roasting pan to cover the bottom of the pan. Over medium-high heat on the stove top, brown the roast on all sides. Turn the meat with tongs -- piercing it with a fork may drain the natural juices.
Add a small amount of seasoned broth, bouillon or water. A bay leaf in the liquid imparts a pleasant flavor, as do herbs such as thyme, parsley, oregano, basil or marjoram, perhaps bundled to create your personal blend of bouquet garni. Drop the herbs directly into the liquid. Cover the pan with a tight-fitting lid and place it in the center of an oven set to about 300 degrees Fahrenheit. Alternatively, braise the browned roast on top of the stove over a burner on low, just hot enough to keep the liquid simmering.
Check the roast periodically and replace liquid, if necessary. Add vegetables to cook with the roast, if desired, about 1 hour before you expect the meat to be done. A sirloin roast generally requires about 22 minutes per pound to reach a medium rare temperature of 135 F to 140 F. Don’t judge doneness by the clock -- check it with an instant read meat thermometer. Take the roast out of the pan about 5 to 10 degrees before it reaches the optimum temperature, placing it on a platter to rest. The temperature rises around 5 degrees and the meat continues to cook as the meat rests. Let a 5- to 7-pound roast rest at least 15 minutes before serving.