Add the grapes, sugar, lemon juice, water (and star anise, if using) to a pot, stir and bring to the boil.
Allow it to boil for about 5 minutes, stirring often to stop it from scorching.
Reduce the heat to low and let it simmer and bubble for 10 minutes. It will thicken further as it cools.
Remove and discard the star anise.
Serve warm or allow to cool and store in a sterilised jar in the fridge for up to 5 days (or freeze for up to 2 months).
Notes
Choose seedless grapes that are ripe and in season for the best flavor.If you want a smoother sauce, cook the grapes until they are very soft before mashing them.The sauce will thicken as it cools, so keep that in mind when cooking it to your desired consistency.Serve your grape compote warm or cold.