Put the poppy seeds and dried red chillies in a mortar and pound with a pestle or in a spice grinder and process, adding a little water if necessary, to make a paste.
Heat the oil in a kadhai, wok, or large, heavy-based pan over medium heat, add the potatoes, and fry for 15-20 minutes, or until golden brown and soft. Remove with a slotted spoon and drain on kitchen paper (paper towels).
Add the poppy seed paste to the same oil and fry for about 2-3 minutes, then add the fried potatoes and season with salt.
Pour in 125 ml / 4 1/2fl oz (1/2 cup) boiling water, stirring constantly, then cover and cook for about 5 minutes, or until all the water has evaporated. Remove from the heat and add the lemon juice.6