Scrub the potatoes well then boil whole in salted water. Meanwhile cut the chillies in half, length-wise, remove most of the seeds and chop finely. Heat the oil in a frying pan over a low flame, add the cumin seeds and the chillies and fry gently, but do not burn! Remove from ther heat.
When the potatoes are cooked and tender, drain, cool and then cut into thick slices. Arrange half the slices in a layer in a baking dish, drizzle with half the chilli oil and season with salt and pepper. Add another layer and sprinkle with the rest of theoil. Bake in a pre-heated oven at 200⁰C/Gas 6 for just 10 minutes, then serve immediately.