Grease eight small ovenproof dishes (1-cup capacity).
Beat chopped butter, sugar and rind in a small bowl with an electric mixer until light and fluffy. Beat in egg yolks, one at a time, until combined. Transfer to a bowl.
Stir in milk and flour. Stir in juice and pulp.
Beat egg whites in a clean, small bowl with an electric mixer until firm peaks form. Gently fold into passionfruit mixture.
Divide among prepared dishes. Place in a large roasting pan. Pour enough boiling water into pan to come halfway up sides of dishes.
Cook in a moderate oven (180C) for 40 minutes, or until puddings feel firm on top and lightly golden. Remove dishes from pan. Stand for 5 minutes.