In a large pot on a medium heat melt the butter and toss in all the onions cover and let sweat for about 10 minutes.
Peel and cut up the squash, removing the seeds. I find this easiest by cutting the squash into disks then remove the skin using a knife.
Add all the cubed butternut squash and parsley in the pot and stir, cover and let sweat for 15 minutes until it just begins to soften-
Add all the chicken stock, thyme and the nutmeg to the pot cover and bring to a simmer and cook for at least 30 minutes until the squash is very soft.
Remove the pot from the heat and add the cream, and with an immersion blender, (mix Stavel) puree the soup until it is very fine. If you don't have an immersion blender, you can use a food processor and puree it a bit at a time. Do be careful this soup is thick and hot and you can seriously burn yourself.
You will find the soup very thick. It will need to be thinned with some of the warm water. Add a bit at a time until it becomes the right consistency.
Correct salt and pepper. Use either fleshly grated black or ground white pepper if you don't like the black spots on the soup.
Garnishes for this soup can and should be rather simple, chopped chives or thinly sliced scallion. Maybe a spoonful of finely chopped egg and parsley. But being American why not crispy chopped bacon or small cubes of ham. Another idea to make this more of a meal is to add small chicken or veal meatballs.