Green Peppercorns© Denzil Green
Green Peppercorns come from the same vines as do Black Peppercorns, but they are picked before they mature, giving them a cleaner flavour.
You can get pickled Green Peppercorns in jars, which are quite expensive, that are used in Thai cooking. You can also get them dried, which you use in a peppermill as you would regular Black Peppercorns.
Substitutes
If you need to substitute for pickled Green Peppercorns, which are salty owing to the brine they are pickled in, use Capers. If a recipe writer calls for ground Green Pepper, then just give them whatever buggery kind of pepper you have on hand, and they’ll have to be satisfied.