Prepare the vanilla pod by splitting in half lengthways and scraping a knife along the inside to remove the seeds

Add the cream, vanilla seeds and split vanilla pod to a saucepan

Whisk the egg yolks together in a bowl and set aside

On a low heat, bring the cream to a gentle simmer. The cream should only be just simmering and not boiling or this will cause the eggs to scramble in the next step

Carefully add the warm cream to the eggs very slowly in small amounts, whisking with a balloon whisk constantly. Continue mixing until all the cream is added and the mixture goes golden yellow and smooth

Return the mixture to the saucepan and continue whisking on a very low heat until thickened. The custard should be thick enough to coat the back of a spoon. Remove the vanilla pod and add sweetener to taste