Select dark green leaves and avoid any with yellowing edges.

Separate into leaves and remove the thick stalks; wash well in cold water and drain. Blanch the whole leaves in boiling water for 1 minute. Drain and plunge immediately in a bowl of iced water to cool. Drain again and dry on kitchen paper and shred.

Pack in convenient quantities in polythene bags. Remove the air, seal, label and freeze. Storage time: 6 months.