Toast the coriander seeds by heating a pan over medium high heat and dry frying the seeds, agitating the pan frequently, until toasty brown and fragrant. Remove from the pan and crush the seeds with a pestle and mortar.

Bring the water, toasted crushed coriander, and lavender to the boil in a small saucepan. Remove from the heat, cover, and leave to infuse for ten minutes.

Strain and add apple juice, syrup, and lemon juice. Allow to cool and serve with ice.