My mother-in-law's recipe for Zucchini Zoup, modified a little by me to drop the fat content a bit.

 2 pounds of zucchini, sliced

2 medium potatoes, diced

1 medium onion, diced

2 tablespoons  olive oil

1 cup or more (I get carried away) cashew nuts (broken bits/halves will do fine as we blend later)

vegetable stock cubes (2 or 3) 

Salt if you need it, pepper (essential)

In your big soup pot, saute the onion and potato in the olive oil until just cooked (M-i-L uses about a stick of butter here, emulate at your own risk).  Add the zucchini and saute that while you dissolve the stock cubes in hot water. BTW use Knorr or other good cubes NOT generic supermarket cubes which make the whole thing sort of weird. Add the stock to the pot and fill up with water to about the one gallon level. Bring to a boil and simmer until the veggies all look cooked (~1/2 hour). Add the nuts and simmer another 5 minutes. Turn off the heat and allow to cool. Blend the whole thing. Really, let it cool. Blending soup that's still hot leads to burns and strange green stains on the kitchen walls. Season to taste. Depending on your stock cubes and whether your cashews were salted, you may need to add more or less salt. Definitely add some black pepper. A dash of cayenne even. Reheat when needed and serve with an artistic swirl of cream if it's a special meal.