Heat 2 tablespoons oil in a large saucepan, add the onion and fry over a gentle heat until soft. Stir in the curry powder and cook for a further 1-2 minutes.
Add the pumpkin and sweet potato chunks, stir well and then pour in the stock. Bring to a simmer, cover the pan and cook over a low heat for about 15 minutes or until the pumpkin and sweet potato are very tender.
Leave to cool a little, then blend in batches in a liquidizer until smooth, adding some of the coconut milk to each batch.
Ideally served with croutons or a sprinkling of your favourite herbs.