Whisk together the cornstarch and caster sugar in a medium mixing bowl. Ensuring the cornstarch is completely whisked into the sugar will ensure you don’t have lumps of cornstarch in your custard. This is important as the cornstarch doesn’t dissolve into the egg whites easily, so it needs to be combined prior to adding them.

Whisk in the eggs and continue until mostly smooth. Set aside and the cornstarch should dissolve while you work on the rest of the custard.

Place a tea towel on the bench, get out your whisk and set aside a medium/large pouring or measuring jug.

Place the plant cream and water in a medium saucepan over a low-medium heat. Heat the mixture, whisking intermittently, until it is hot to the touch but not boiling or simmering.

Turn the heat off and ladle half of the hot dairy mixture into your pouring jug.

Place the bowl of egg mix on the tea towel (to stop it moving) and whisk the mixture as you very slowly drizzle in the hot dairy mixture.

Continue drizzling and whisking until you have used all the dairy in the jug. Tempering the eggs like this brings up them to a warm temperature gradually so that they don’t split and you get a lovely smooth custard.

In this time, the mixture should thicken and coat the back of a spoon easily. The custard should thicken to a point where the whisk leaves tracks in the surface and it has the consistency of a thin to medium thickness pudding.

Continue to cook on a low heat until your custard thickens. It does continue to cook and thicken as it cools, so If in doubt, take it off the heat. You don’t want to overcook the eggs and curdle your custard.

Cover your custard with a film of cling wrap once it has finished cooking. This will prevent it from forming a skin. If your custard does form a skin, you can simply whisk it in (although you might get a few little lumps). You can sieve the custard to remove the lumps if you want to.