1.For paste, in small blender, spice grinder, or mortar and pestle, blend or pound ingredients together until finely chopped.
2.Heat oil in wok or large frying pan, add paste; cook, stirring, until fragrant.
3.Add chicken; cook, stirring, until browned all over.
4.Add sauce, juice and sugar to pan; simmer gently, uncovered, a few minutes or until thickened slightly. Stir in mint and coriander.
5.Divide mixture evenly among witlof leaves.
The chicken filling can be prepared several hours ahead; reheat filling and assemble close to serving time.Note