The most common version of peppercorn sauce is accompanied with a steak in the dish known as "steak au poirve". After searing your steaks, that have been liberally seasoned with large cracked black peppercorns, remove steaks, turn the heat to high and add in some cognac (VSOP if you have it), reduce au sec, then add in some heavy cream and a little beef stock/broth, reduce until the cream is thickened slightly. Finish the sauce with a knob of cold unsalted butter and serve immediately.