Fry the onion in oil until almost soft and translucent.
Add curry powder and continue to fry for a few minutes to release the flavour of the curry powder.
In a greased, ovenproof dish layer sliced potato, chopped coriander and fried onion.
Repeat the process using up all the potato, coriander and curried onion.
Mix the sachet contents with a little of the milk until smooth.
Stir in the remaining milk then pour over the bake.
Bake in a preheated oven at 180°C for about 45 minutes to 1 hour.