Place a heatproof mixing bowl over a pot of gently simmering water (making sure the water is not touching the bottom of the bowl) and to the bowl add the orange zest and juice, ginger, sugar and butter.
Gently stir the mixture from time to time until the butter has melted.
Lightly beat the eggs and egg yolk, just by hand with a whisk, and add them to the orange mixture along with the cornflour mixture.
Stir until all of the ingredients are mixed together.
Leave to cook for about 15 minutes, stirring from time to time, or until the mixture has thickened to the consistency of custard.
Turn off the heat, remove the mixing bowl from the pot and set aside to cool, stirring intermittently.
Store in the fridge or freezer in sterilized glass jam jars. Tip:
If you would like to speed up the thickening process, you can microwave the mixture for 1 minute bursts until it has thickened to the consistency of custard.Recipe reprinted with permission of Sarah Graham.