Heat the oil in a pan under medium heat.
Fry the onions until they are soft and have a transluscent appearance.
Add the turmeric and coriander and stir continuously for one minute.
Add the butternut squash and peppers and stir to make sure they are coated with the spices in the pan.
Pour in some water.
Cover the pan and allow to cook until the butternut squash is soft.
Stir in the peanut butter.
Allow to cook for about 3 mins for the flavours to develop.
Add some salt to taste, if required.
Pour in a blender to puree.