Preheat your oven to 80°C

Pick the peppermint stalks (I cut just below the last leaf) and place in a colander.

Give the colander a good shake to remove any beasties, and then give the stalks a wash under cold running water.

Gently dry the leaves using a tea towel and remove any discoloured leaves.

Spread the stalks out on a baking tray and bake in the oven for around 1.5 hours - keeping an eye on them to ensure the leaves don't burn.

You can tell the leaves are fully dried out when the leaves become very crisp and brittle. When they are sufficiently dry remove from the oven and gently remove the leaves from the stalks, placing the leaves in a clean dry airtight jar.  I then compost the stalks.