Step 1

Trim the steak of any excess fat. Cut the meat into 2 pieces. Crush the peppercorns using a spice grinder, mortar and pestle, or the bottom of a heavy skillet.

Step 2

Sprinkle salt to taste on the top and bottom of the steaks, then press each side of each steak into the cracked peppercorns, encrusting the steaks as lightly or heavily, as you prefer. Heat the oil and the butter in a large, heavy saute pan or skillet over high heat. When the pan is quite hot but not smoking, add the peppered steaks. Cook, without nudging or fussing with the steak, for about 1 1/2 to 2 minutes, until the undersides are well seared.

Step 3

Turn the meat and cook until the steak is done to almost the desired doneness, about 1 1/2 minutes more for medium-rare, depending on the thickness of your steak.

Step 4

Leave the steak to rest on a warm platter for at least 10 minutes.

Step 5

A few minutes before you intend to eat, return the pan with the drippings to medium heat. Add the shallots and saute briefly, stirring with a spoon to scrape the bottom of the skillet.

Step 6

Lean away from the stove (averting your face) and carefully pour the Cognac into the pan, holding the measuring cup close to the stove to avoid splashing. If desired, tilt the edge of the pan slightly over the burner flame or use a match to ignite the alcohol. Immediately turn the heat down. The Cognac will flame for a few seconds as the alcohol burns off. When the flames die down, cook for a few moments more and then add the stock. Bring the liquid back to a boil and cook, stirring occasionally, until the sauce thickens, 2 to 5 minutes.

Step 7

Taste the pan sauce and adjust the seasoning as desired. Add the soft butter, tilting the pan rather than stirring the sauce, until the butter melts and is incorporated with the pan juices.

Step 8

Pour the poivre sauce over the steaks. Sprinkle liberally with chopped parsley, if desired, and garnish with sprigs of watercress.