Things You'll Need
A beefy, flavorful top sirloin roast can be prepared in less than three hours. Before you cook the roast, age the beef so that it has that tender juicy flavor you get in restaurants. How you prepare and cook the meat will determine the tenderness and flavor after aging. Age the meat in the refrigerator to inhibit bacterial growth; searing the meat when cooking will also kill off bacteria, which can only grow on the outside of the meat.
Place the roast on a wire rack in a roasting pan. Place it uncovered in the refrigerator; let it sit and age for 24 hours. You can age the roast for up to three or four days if you have time.
Remove the roast from the refrigerator one hour before you will cook it. Let the roast come to room temperature. Trim off any dried-out pieces of meat.
Preheat the oven to 250 degrees Fahrenheit. Place the oven rack in the lower-middle position.
Heat a large frying pan on the stovetop on medium-high heat. When the pan is hot, add the roast and sear on all sides for approximately six to eight minutes per side.
Remove the roast from the frying pan. Place the roast on the wire rack in the roasting pan with the fat side facing up. Sprinkle any spices you would like to use, such as garlic, salt, pepper or dehydrated onion, on top of the roast.
Place the roasting pan in the oven. Cook for one to two hours, until the internal temperature reads 110 degrees Fahrenheit. Use the meat thermometer to check the temperature of the thickest part of the roast. Cook the roast until it has the correct internal temperature.
Turn up the oven to 500 degrees Fahrenheit once the meat's internal temperature reaches 110 degrees. For medium-rare beef, cook the roast at 500 degrees until the internal temperature measured by the meat thermometer reads 130 to 140 degrees; this will take 15 to 20 minutes.
Remove the roast from the oven. Cover with a tin foil tent; let it sit for 15 minutes. Cut off the twine holding the roast together. Use a sharp knife to cut the roast across the grain, in the same direction as the twine was tied.