Peel, wash and cut potatoes into 1/2 cm cubes and immerse in water. Boil peas until cooked and drain. Scrape, wash and finely chop ginger. Remove stems, wash, and slit, de-seed and finely chop the chilli.
Heat the ghee in a deep frypan or wok, add cumin and saute gently until it begins to crackle. Add ginger and saute for a minute.
Add the potatoes red chilli and salt - reduce to a low heat, cover and cook, stirring occasionally, until the potatoes are tender - not mashed.
Add the peas and green chilli and stir until the mixture is completely dry. Add the coriander, remove, cool and cover.
Cut pastry into 12cm circles and then cut in half to form a semi circle. Form into a cone place filling in centre of pastry cone. Moisten edges with egg white and water seal and join by pleating.
Place on baking paper and cook in the oven without oil at 180C for 15 minutes or until golden brown.