My usual recipe - all amounts are aproximate and can be varied a fair bit.
Dice and saute a small onion and a large carrot until soft. Add 2 cups of chicken stock and 1 cup of water and 2-3 cups diced squash and simmer until the squash is soft. Puree in a blender or with a hand blender. Add the juice of half a lemon, 1 t cumin, 1/2 t coriander and 1/2 t paprika and salt and pepper to taste.
For an alternate seasoning use rosemary and thyme instead of cumin and coriander.
You can add a splash of cream or milk at the end - I actually prefer it without, as the flavour is richer.
It's also good with some roasted red pepper thrown in when you start simmering, or, if you like garlic, throw in some whole peeled cloves at the beginning when you saute the onions.