Slight adaptation from a BBC Food recipe.

340 gr cranberries, washed
175 gr (light) brown sugar
125 ml orange juice (fresh), 1 orange
25 ml lime juice, 1 lime
25 ml mandarin orange juice, 1 mandarin
splash of red port
zest of 1 lime
zest of 1 mandarin

Combine juice and sugar, add to saucepan with thick bottom. Bring to the boil, stir in the sugar carefully. When boiling add the port, followed by the rinsed cranberries. Stir on a low heat to simmer. Add the zest and stir some more.

Frequently stir the mixture, but have it on low heat to simmer.
After about 5-10 minutes—depending on whether you want the berries as complete mush or more firm texture—, add to clean bowl and leave to cool.
When completely cooled transfer into glass or plastic containers.

The sauce can be kept for about 1 week in your fridge.