An example of a "true" peppercorn variety is green peppercorns, which come from the species piper nigrum, the same plant that ...

Add the wine and reduce the volume of liquid by half. Stir in the crème fraîche and the peppercorns. Season with salt and plenty of freshly ground black pepper.

Fresh green peppercorns are sold at shops specialising in southeast Asian ingredients. If you can't find them, use about one tablespoon of dried green peppercorns - but not the type in brine.