Plum Sauce

1) Heat the oil in a pan over a medium heat and fry the onions for 1-2 minutes, or until softened.
2) Add the peppercorns and continue to cook for another 1-2 minutes.
3) Add the plums, vinegar and sugar and bring to the boil.
4) Reduce the heat and simmer covered for 5 minutes or so until you have a nice shiny pulp.
5) Leave to cool then puree in a food processor and strain to obtain a nice smooth sauce.
6) Season to taste.