Every time my husband or son gets sick, I make this soup from scratch. I recommend eating it as hot as you can stand, and add extra sea salt and a touch of cayenne pepper to your own bowl. Just a tiny sprinkle of cayenne can make your soup too spicy to eat, so season with caution. The cayenne pepper kills germs and helps get rid of congestion. Most of the time I actually feel better just by the time I'm done eating a bowl of this soup.
If you, like most of us, don't feel like spending an afternoon making soup when you're sick, it freezes really well, so you can make it ahead of flu season.
Unwrap the 2-4 lb. chicken and clean body cavity of internal organs. I throw the organs away since I don't care for the way they make the broth taste but if you like you may either boil them with the chicken to flavor the broth or use in another dish. Place in a large stock or soup pot. The pot must be large enough that with the chicken inside a) you are able to easily put the lid on, and b) you have left room around the chicken for the vegetables to flavor the broth.
Wash carrots and celery. Trim off imperfections and the tops if you wish, but I keep the celery leaves because they give the soup a wonderful flavor. (All the vegetables you are adding at this point are just to flavor the broth, they will be strained out before you make the soup.) Peel the onion and the cloves of garlic.
Cut the carrots, celery, and onion into fourths. Crush the cloves of garlic just enough to release flavor with the side of a chopping knife. Tuck the vegetables into the stock pot alongside the chicken.
Fill the pot with just enough filtered drinking water to cover the chicken and vegetables. Add one teaspoon of sea salt for each pound of chicken.
Place pot over medium heat on stove and cover. When the water comes to a boil lower the heat and allow to simmer until the chicken breast meat measures 170 degrees Fahrenheit with a meat thermometer. This will usually take between one and two hours. If you're an experienced cook, just cook the meat until it's tender.
When the chicken is cooked, place a pasta colander into a large bowl and *carefully* lift the chicken into the colander. Strain the broth into another large soup pan and set aside. If it will be a while until you use the broth, cover it and put it in the refrigerator.
I like to break the chicken up just a little so it cools more quickly and put it in the fridge until I debone it and chop it about an hour before dinner. Or you can make the chicken the day before, pick the meat off the bones ahead of time, and refrigerate the meat until you're ready to use it. It doesn't matter, just make sure that the meat is off the bones and roughly chopped into 1/2 inch chunks before you start on the vegetables.
Start the broth heating on the stove. Wash mushrooms, carrots, celery, and zucchini. Peel and chop the onion and cloves of garlic set aside for the soup. Melt 1/2 stick of butter in the bottom of a large frying pan on medium heat. When it's melted add 2 T. olive oil and the chopped onion and garlic. Stir them occasionally and adjust the heat to make sure they don't overcook or burn while you do the next step.
While the onions and garlic are cooking peel the carrots and cut the tops and bottoms off the celery and zucchini. Slice the carrots first (1/8"-1/4" slices), and add them to the pan with the onions and give it a stir. Then slice the mushrooms the same way and add them; then the celery. Last of all split the zucchini in half lengthwise and slice the same way BUT do not add yet. Put in a bowl and set aside.
When the onions look translucent, turn off the heat and cover the pan.
When the broth comes to a boil, add the 8 ounces of uncooked spiral pasta, cover, and turn down the heat as low as you can without losing the boil.
When the pasta is nearly tender, add the cooked vegetables and roughly chopped deboned chicken and cover again, keeping the soup at a low-medium heat. Here is the point where you may add some more water if you like a little more broth. When it boils again, test the pasta for doneness and add sea salt and black pepper to taste. If you wish you may add some cayenne pepper, but I find that I prefer to allow each person to add their own as it is very easy to make it too spicy. After seasoning, add the sliced zucchini to the pot, cover, and turn off the heat. Serve with warm, freshly baked bread or biscuits.