Squash & nigella seed soup

From : http://www.bbcgoodfood.com/recipes/8200/squash-and-nigella-seed-soup

Ingredients

2 tbsp olive oil
1 onion
2 tsp nigella seeds
pinch chilli powder
800g squash, peeled, deseeded and cut into chunks
1 potato, cubed
850ml vegetable stock
small bunch flat-leaf parsley

Method

1. Heat the oil in a large pan, add the onion, then fry until lightly coloured. Add the nigella seeds and chilli, then fry for 1 min. Tip in the squash, potato and stock, then bring to the boil. Stir well, cover, then simmer for 20 mins, or until the vegetables are tender.
2. Purée the soup in batches, adding a handful of parsley with each batch. Return the soup to the pan, then reheat. The soup can be frozen for up to 1 month.