Chop the onion and celery. Make sure you peel the celery to remove the tough strings.
In a large soup pot heat 1/4 cup of water, add the onion and celery and cook till softened.
Next finely chop the lemon grass, chilli pepper (de-seeded if you wish), and garlic. Cook for another 2 minutes or until softened.
Peel the butternut squash and chop into bite size chunks. Core and peal the pears and cut into quarters.
Add pears and butternut squash to the soup pot.

Pour in the vegetable stock and bring to a boil. Turn down the hear and simmer for 30 minutes or until the squash is tender.
Blend in a food processor till smooth.

1 large onion
2 ribs celery
2 stalks lemon grass
1/2 inch piece ginger
1 chilli pepper
2 cloves garlic
1/2 large butternut squash
4 small pears (2 large ones)
4 cups vegetable stock