1. Put the wine and brandy in a heavy pan and boil gently for about 5 minutes or until reduced to a third of the original volume.
2. Add the stock and boil for 5 minutes.
3. Add the cream and boil for 15 minutes, stirring occasionally so that it does not catch on the bottom, or until the sauce has reduced by about a third and is of pouring consistency.
4. Put the vinegar and sugar into a small saucepan.
5. Boil for 30 seconds or until it smells caramelized and is reduced to about 1 tablespoon.
6. Cool for 1 minute and pour in the cream sauce.
7. Stir well.
8. It may be necessary to replace it over the heat to re-melt the caramel.
9. Add the port and peppercorns.
10. Season with salt and pepper to taste.