Classic steak Diane is served with a sauce of sautéed and cooked-down onions, garlic, whiskey, stock, cream, and crushed green peppercorns. Unlike black peppercorns, the green ones have a bright fruitiness to them. I love the same sauce on pork. I brine the tenderloin first to keep it juicy and then grill it whole. The grilling only takes about 10 minutes, and while the meat’s resting, you make the sauce.