Place a small pan on a low/medium heat with coconut oil. When hot add onions, garlic and cook till light brown. Add mustard seeds and wait til they begin to pop. Add ground coriander and cumin and gently cook for about 2 minutes or until they become aromatic. Add pumpkin pieces followed by chili powder (optional) and turmeric. Add water, bring to the boil and cook until very soft. Blend in a Vitamix until smooth and then add more boiled water if necessary.