Halve the vanilla pods lengthways, scrape out the seeds, then add to a saucepan with the pods.,

Add the sugar, and the zest and juice from your lemon and lime.,

Bring to the boil, then simmer for a couple of minutes until all the sugar dissolves.,

Take off the heat, pour into a bowl and leave to cool. Don’t put your finger in for a taste, though, as it could burn you.,

Once the syrup is cool, remove the vanilla pods.,

Peel, destone and scoop the avocado flesh into a liquidiser with the syrup and milk.,

Blitz to a smooth, light consistency – like a smoothie.,

If you’ve got an ice-cream maker, put your mixture into it and churn till smooth and frozen.,

If not, pour it into a large baking dish or deep tray and pop it in the freezer, giving it a whisk every half hour or so until frozen and smooth.,

You can eat it right away or transfer it to little containers, cover and pop in the freezer for later.