Reduce heat; add onion, potato, marrow and chilli, stir well to coat in spices
Cover and sweat for 5-7 minutes
Add stock and coconut milk. Cover and cook for another 10-15 minutes
Add spinach, cover and cook for 5 minutes
Blend thoroughly using a blender. I tend to leave about a ladleful of liquid behind as I like my soup thick. The spinach takes a while to break down but it does in the end!