1. Combine the sugar and cornflour (cornstarch).
2. Put the vinegar and water in a saucepan and heat over low heat. When the mixture is lukewarm, gradually stir in the sugar mixture until it is completely absorbed. Bring to the boil and cook, stirring constantly, for 2 minutes, or until the sauce is fairly thick and smooth.
3. Stir in the beetroots (beets) and baste well. Simmer for 4 to 5 minutes, or until they are heated through. Serve at once.