Heat the berries and water for around 10 minutes on a medium heat until the berries soften.
Pour berries through a strainer or muslin cloth so that all the juice filters through leaving the seeds behind.
Whisk the egg yolks in a bowl over a pan of gently bubbling water (a Bain Marie) and add the honey and berry juice.
Whisk constantly until the mixture starts to thicken.
Add the butter one tablespoon at a time, continuing to whisk, adding the next only when the first has melted.
Continue to cook the mixture until it has a consistency of thick yoghurt or custard (this should only take a few minutes).
Pour into a jar (heat safe), allow to cool and then store in the fridge for up to a week (it won't last that long).
Use it in pies, on meringues, or to top pancakes. Enjoy!