Rub both sides of the steaks with the peppercorns, pressing hard so they adhere. Season the steaks with salt and leave the steaks to stand for 30 minutes. Melt half the butter in a frying pan and fry the steaks over a moderately high heat until cooked to your taste. Transfer the steaks to a warmed serving platter and drain off the fat from the pan. Pour the cognac into the pan and scrape the bottom of the pan with a wooden spoon to release any cooked-on meat particles. Light the warmed Cognac with a match to flambÄ it. Stir in half the cream and mustard and cook until reduced by one-quarter. Whisk the flour or cornstarch into the remaining cream and stir this mixture into the frying pan. Bring to a boil, then pour over the steaks. Serve with French fries.
