Quick Answer. Oven-roast beef tenderloin by trimming a whole beef tenderloin, seasoning it with salt, sugar and crushed peppercorn, and roasting it at 475 degrees Fahrenheit for 20 to 25 minutes. Serve the tenderloin with browned garlic butter. Ree Drummond offers a recipe for peppercorn roasted beef tenderloin on FoodNetwork.com.