Bring the stock to boil and add saffron; turn off the heat and let it infuse
In a Dutch oven or other heavy pot heat up the butter
Add onions and cook for 2-3 minutes
Add garlic and cook for another minute
Add peppers and celery, cover and cook for about 20 minutes, stirring occasionally
Add wine and let it almost cook out
Add cumin, infused stock and salt
Let it cook for another 10 minutes
Cool it slightly and pure in blender in batches
Return to the clean pot, add heavy cream and season with freshly ground pepper and salt if needed
Serve it with a dollop of greek yogurt and pinch of cayenne pepper