Butter the bread rounds. Wash and trim the leeks, and slice into 2 1/2 inch (6-cm) lengths.

Remove the outer leaves and blanch the centers in a little boiling water for 2 minutes.

Drain the leeks and allow to cool. Roll out the leaves and trim exactly to cover each bread round.

Coarsely mince the smoked salmon, divide onto the rounds and garnish each canapé with a slice of lime and a dill or parsley sprig.