I made this several weeks back for my girlfriend and her friends for brunch and it came out pretty well and was quite easy to make. heres how i did it.
2 large heads broccoli chopped into small pieces, you can leave out the bottom 2 inches or so of the stem but the rest can be used.
1 qt chicken stock
1 large onion - minced
3 stocks celery - minced
1 cup heavy cream
1/2 stick butter
2 medium potatoes peeled and chopped into small pieces
1/2 qt water
2 cloves of garlic, minced
3 tsp salt or to taste
3 tsp pepper or to taste
in a large deep pot saute onion, garlic and celery in a bit of olive oil and the butter until soft. add potatoes and broccoli and stir. add chicken stock and bring to a boil, covered, for about 30 mins or until the broccoli and potatoes are fully cooked.
use an immersion blender or regular blender and blend all together until smooth. add the water and heavy cream, stir in well, and blend again. cook over low heat for about 30 mins. add salt and pepper to taste at the end.
i put a bit of regular sour cream on top just before serving
(you can use more butter and/or cream depending on how fatty, and tasty, you want it)