Preheat oven to 375 degrees F.
In a large roasting pan, toss together the zucchini cubes, onion, salt, pepper, and just enough olive oil to coat the vegetables evenly. Spread the vegetables in a single layer in the bottom of the pan. Roast in the oven for 30 to 35 minutes, turning once, until the vegetables have browned on at least one side and are tender. Remove from heat, cover the pan with aluminum foil, and let sit for 25 minutes.
In a large saucepan over medium-high heat, bring the chicken broth just to a boil, then reduce the heat to medium-low and add the roasted vegetables. Cook for 10 minutes, adjusting the heat to keep the liquid just below a boil.
Using an immersion (stick) blender or a blender to create a slightly chunky soup. If you use a regular blender, you will need to do this in batches. Return the blended soup to the cooking pot.
Add 2 tablespoons Parmesan cheese; taste and add additional cheese or pepper as needed.
Serve warm with a garnish of basil and/or shaved Parmesan cheese, if desired.
For optimum flavor, refrigerate for no more than 2 days.
To serve, warm over low heat, stirring until hot. Remove from heat and serve in soup bowls.
Makes 6 to 8 servings (6 cups).
* Thoroughly scrub each squash under running water until the skin feels clean. Then cut off and discard the stem end and scrape off the other end. Only if the skin is unusually tough or the surface feels especially gritty after washing, is it necessary to peel the squash.
** Learn how easy it is to make your own homemade Chicken Stock - Basic Chicken Stock.
Roasted Zucchini Squash Soup Recipe: https://whatscookingamerica.net/Soup/ZucchiniSoup.htm