When shopping for a top sirloin, be sure to tell the meat cutter that you're planning to cook it as a roast. Otherwise it may come looking more like an extra-thick steak. For the best flavor, plan to season the meat a day or two ahead of roasting. The roast makes its own little jus as it roasts, but Mustard Cream Sauce makes a fine accompaniment as well: This zesty little sauce perks up a serving of roast beef. It's also delicious as a sandwich spread for any leftovers. This recipe makes about 1/2 cup of sauce, which will keep for several days in the refrigerator.
Recipe adapted from All About Roasting by Molly Stevens. —molly_stevens
Top Sirloin Roast
2 1/2- to 3-pound top sirloin roast, tied at 1 1/2-inch intervals
If seasoning in advance, sprinkle 1 1/2 teaspoons salt and 3/4 teaspoon black pepper over the entire surface of the roast, and refrigerate, uncovered or loosely covered, for 24 to 28 hours. Let the roast sit at room temperature for 1 hour before roasting.
Heat the oven to 450°F (425°F convection) with a rack near the center. Choose a shallow roasting pan (or baking dish) just large enough to accommodate the roast, and outfit it with a flat roasting rack. (You can also improvise a roasting rack by crumpling a long piece of foil into scrunch it into a rope shape; bend the "rope" into a spiral or "S" shape to set the roast on.)
Place the roast on the rack, and smear the surface with butter. Slide it into the oven, and roast until you hear a good sizzle, about 15 minutes. Immediately, pour 1/2 cup room-temperature water into the bottom of the pan, and lower the oven heat to 275°F (250°F convection), and continue to roast until an instant-read thermometer inserted in the center of the roast reads 115°F for very rare, 120°F for rare, and 125°F for medium-rare, another 55 to 70 minutes. With top sirloin, I don’t recommend roasting beyond medium-rare.
Transfer the meat to a carving board, preferably one with a trough, and leave to rest for 20 to 30 minutes. Skim any excess fat from the drippings, and taste. They should be salty, but tasty. Keep warm to serve with the beef.
Carve the roast across the grain, snipping the strings as you go, and drizzle a bit of pan juices over the top before serving.
Mustard Cream Sauce
In a small bowl, whisk together the yogurt (or crème fraîche), mustard, and lemon juice. Season lightly with salt to taste.
Molly Stevens lives, eats and writes in Northern Vermont. She is the author of two James Beard Award winning cookbooks, All About Roasting and All About Braising. When the spirit moves her, Molly travels around the country teaching cooking classes.