Green Peppercorn and Grapefruit Sauce

Wash the grapefruits and squeeze one of them. Peel half of the other with a sharp knife, removing the white pith and membrane, and cut out segments avoiding the membrane. Squeeze the rest of the grapefruit. Put the grapefruit juice into a pan and bring to the boil. Mix the cornflour smoothly with the orange juice and stir into the grapefruit juice. Return to the boil briefly. Add the wine, drained peppercorns and sugar to taste. Put the grapefruit segments into the sauce. Serve warm or cold garnished with mint.

This sauce, with very little sugar, goes well with green asparagus (for example).