1.Preheat oven to moderate. Grease 20cm x 30cm lamington pan; line base and two long sides with baking paper, extending paper 2cm above edge of pan.
2.Process flour, butter and icing sugar until combined. Press over base of prepared pan; bake in moderate oven about 20 minutes. Cool in pan.
3.Sprinkle gelatine over juice in cup; stand in small pan of simmering water, stir until dissolved. Beat gelatine mixture and condensed milk in small bowl with electric mixer about 10 minutes or until mixture thickens. Pour over base.
4.Blend custard powder and caster sugar with milk and the water in small saucepan; cook, stirring, over heat until mixture boils and thickens. Remove from heat, stir in extra butter; cover, stand 10 minutes. Stir in extra juice and passionfruit pulp. Pour over gelatine layer in pan. Refrigerate until set, before cutting.
You will need about 4 passionfruit for this recipe. This recipe can be made three days ahead and kept, covered, in the refrigerator.Note