Halve cantaloupe and scoop out seeds for compost or rubbish.
Scoop melon into the blender . Carefully flatten the round bottom of each empty melon shell by taking off a thin slice, in order to allow it to sit flat. Rinse and reserve for serving.
Squeeze juice of half a lime into the blender. Add mint leaves and pinch of salt.
Purée completely. Taste for salt, adding more if desired.
Serve in melon halves, with mint sprig and thin slice of lime for garnish.