Lo, these many decades ago when I worked at L'Artiste, we developed this as a faster, easier alternative to the classic basic cream soup recipe — with, I might add, excellent results. Since it's getting to be that time of year, I thought I'd share it. It's far simpler than the classic — no roux or cream sauce — and adaptable to any cream soup you want to make. You can also adapt the proportions easily (more or less cream, etc.) The thickening comes from the pureed vegetables, rather than a roux.
Basic Cream Soup
1 quart chicken, turkey, or vegetable stock
1 cup heavy cream
salt, pepper and any other seasoning appropriate
Simmer the vegetable in the stock until quite soft. Using a slotted spoon, remove the vegetables to a blender. Add a cup of the stock and puree, gradually adding more stock as needed. Pour back into the pan and bring almost to a boil. Add the cream and seasonings to taste, heat and serve.
Depending on what vegetable you use, you may want to puree all or only part:
For cream of broccoli soup, use one large or two small bunches of broccoli. Cut off half the florets and reserve, and chop the rest and cook as above. Before adding cream, add the reserved florets and let them simmer a few minutes until done. Add cream and seasonings and serve.
For cream of spinach soup, use two large bunches of spinach or one large bag or two boxes of frozen spinach. Puree all of the spinach (little bits of spinach, unlike florets, aren't nice, since they tend to be slimy).
For cream of mushroom soup, you'll want lots of dried mushrooms, preferably porcini. First, soak them until soft (thirty minutes in hot water). Strain the soaking water and use as part or all of the stock. No need to puree the mushrooms. If you want it a bit thicker, thicken with a beurre manie.
For cream of chicken soup, poach a couple of chicken breasts in the stock then remove. Dice the chicken, add to the stock, and add cream and seasonings. Again, if you want it a bit thicker, use a beurre manie (and try adding a bit of tarragon).
Use your judgment. I've never been inclined to try cream of beef soup, for example — or cream of beet soup, either. But this is an almost infinitely adaptable recipe, so let your imagination run wild.