Melt butter in a large pot, then add diced onion. Sweat the onion until slightly browned, about 5 minutes. Stir in saffron (crushed), tumeric, cumin, fenugreek, and red pepper flakes and cook for another 3 minutes.
Add jicama pieces and stir for another 3 minutes, making sure to coat everything with the seasoning. Add cauliflower pieces and repeat the process, cooking for another 3 minutes and stirring frequently to coat.
Add stock and cook on medium heat for another 20 minutes or until cauliflower is tender, stirring occasionally.
Stir in half-and-half and add salt and pepper, adjusting to suit your personal taste.
Using an immersion blender, puree the solid ingredients in the pan. Alternately, transfer to a food processor, working in batches, then return to the pot.
Stir in green onion pieces and serve. Add crispy chicken skin if a more savory soup is desired (note, of course, that this will increase the calories considerably).