This is an easy and delicious way to eat up the squash that just keep coming this time of year. All you really need are a few summer squash, an onion and a little crème fraiche or sour cream to dollop on top. You can use whatever type of broth you happen to have on hand - chicken stock, vegetable stock or just plain water with salt.
At my house I serve it with really good sourdough bread from the local bakery and our favorite cheese, Cowgirl Creamery's Mt Tam. That seems to keep everyone happy at the dinner table. It's a surefire hit, unless your children are not soup eaters, which is something I've heard about. Luckily, I do not have that particular problem.
The secret to this soup is caramelizing the onions, which means cooking them over low heat in a pan with a bit of fat for at least 30 minutes.
Start by warming a couple Tablespoons of oil in a pan (olive, canola, whatever). Then add the sliced onions, some salt and turn the heat to low. As low as you can go. It should look something like the photo on the left. Set a timer for 10 minutes and when it rings, check to make sure they aren't sticking. If they are, add water. Then set the time for another 10 minutes. And so on, until your onions are as sticky and sweet as you have time to make them. They will look a bit like the photo on the right when they are ready. You should taste them, too.
When blending the soup I like to use a hand blender, because pouring hot soup into the usual kind of blender can make for a big mess and scalded skin. Hot liquid spinning in a sealed container tends to blow the top off and spray all over. If you only have a traditional blender, either let the soup cool or blend it in very small batches. Hand blenders are awesome - all you do is stick it in the pot and push a button. You can buy one here, for cheap. It is the same one I have at home.
Zucchini Soup: (adapted from the San Francisco Chronicle)
1 large onion, thinly sliced
2 Tablespoons olive oil (or canola or some other type)
zucchini, roughly chopped (as many as you have, maybe 5 medium or so)
2 teaspoons salt (or more or less, to taste)
1 teaspoon curry powder
1 quart stock (chicken, vegetable, or just water)
crème fraiche (or sour cream, for garnish)
fresh ground pepper (also for garnish)
Warm the oil in a large pot. Add the sliced onions and some salt. Turn the heat to low and, as mentioned above, let the onions caramelize. This should take about half an hour. Be sure to check frequently to make sure the onions aren't sticking. If they are, just add some water to the pan.
When the onions are sweet (or when you are out of time), stir in the zucchini, sprinkle the curry powder on top and stir it up (left picture below). The curry powder is intended to give the soup a slight bit of warmth, not actually make it taste like curry, so be careful not to add too much. Let it cook for a minute or two and then add the stock (right picture below). Bring it to boil, then turn down the heat and simmer until the squash is soft, about 20 minutes. You can also dump it all in a crock pot and set it on high for a few hours if you need to leave the house.
When the squash is soft, or when you arrive home, blend the soup. A hand blender is the best way. If you have to use a container blender either let the soup cool first or blend it hot in very small batches.
Taste for salt, ladle into bowls, add a dollop of crème fraiche, grind some pepper over the top, serve and sit down to eat. Don't forget to put the bread and cheese out on the table!