Cut up the broccoli into fleurettes, and trim off the outer layer of skin on the thick part of the stem with a vegetable peeler. Peel and thinly slice the onion.
In a pot large enough to hold everything, melt the butter, then add the cut up broccoli and onions and sweat the vegetables with the cover on it over a low heat for about 15 minutes or until the onions become soft and the broccoli becomes a bright green.
Add the chicken stock or bullion and let simmer gently for another 15 to 20 minutes. You only want the broccoli just cooked. You can test it by poking it with the tip of a sharp knife for doneness. If you cook it too long the broccoli will turn grey and your soup will look dull an unappetizing!
Using an immersible blender (mix stavel) directly in the pot or transfer it to the bowl of a food processor, process the contents of the pot until everything has been liquidized and is smooth.
Remember if you are using bullion cubes that they are salty and you will not really need to add salt at the end of the cooking. Always taste things first before adding salt!
Add the cream then add the nutmeg, salt and white pepper to taste. You might find that the soup is too thick at this point you can add a bit of water or a little more stock to thin it out. Simmer for 5 minutes and serve or put aside to cool and serve chilled (not cold).