Heat oil in a saucepan or wok. Cook onion, ginger and garlic for 2 minutes until soft and translucent.
Add potatoes, eggplant, sweet potato, peas, Five Tastes Curry Paste, kecap manis and fish sauce. Cook for 7-8 minutes. Allow to cool.
Cut 5 circles using a 9cm diameter cookie cutter, from each pastry sheet. Place a tablespoon of mixture on one half of each circle, fold pastry over and squeeze edges to seal. (Or see tip below for other shapes)
Place on baking paper lined oven trays and brush lightly with egg. Cook in a preheated oven at 200°C for 20 minutes or until golden brown. Serve warm.