Sauté 1 medium onion in 2 TB butter or vegetable oil. Feel free to add 2 tsp. fresh sage, 2 tsp. fresh thyme, and some parsley to the onion if it suits you. Sprinkle with 1-2 TB flour. Gradually add 4 cups chicken broth (or vegetable broth) whisking thoroughly. Add 5+/- cups pumpkin puree (this is a good time to mix squashes such as delicata, buttercup, etc.). Cook over low 15 minutes. Add salt and pepper. Add 1/2 cup cream when finished cooking. It’s really delicious!
OK, don’t have any leftover squash on hand, start as above, add the broth, then add your peeled and chunked squash (5+ cups) and simmer until tender. Puree (I love my immersion blender for this) and enjoy. Adding an apple or two (peeled and diced) near the end of the cooking time is nice (season with a little curry, cinnamon and nutmeg if you like). You can’t go wrong!
My friend Nancy makes her soup by cooking the squash in a little water and them puree with a container of Boursin. What could be easier—or tastier!!!