01 - Pat the steaks thoroughly dry with paper towels. Season both sides generously with salt and freshly ground black pepper.
02 - Heat vegetable oil in a heavy skillet over medium-high heat until shimmering. Sear the steaks for 3 to 4 minutes per side for medium-rare, adjusting time for desired doneness. Transfer to a plate and tent loosely with foil to keep warm.
03 - Reduce heat to medium. Add the butter and minced shallot to the same skillet, sautéing for 1 minute until softened and fragrant.
04 - Add the drained, lightly crushed green peppercorns to the skillet and sauté for 30 seconds to release their flavor.
05 - If using Cognac or brandy, carefully add it to the skillet and flambé, allowing the alcohol to burn off completely.
06 - Pour in the beef stock and bring to a boil, scraping up any caramelized bits from the bottom of the pan. Let the liquid reduce by half.
07 - Stir in the heavy cream and simmer for 2 to 3 minutes until the sauce thickens to a luxurious consistency. Adjust seasoning with salt as needed.
08 - Return the steaks to the pan to warm through briefly, or arrange on plates and spoon the creamy peppercorn sauce generously over each steak. Serve immediately.