Begin heating chicken stock in an 8 quart pot or larger over medium heat.
Heat olive oil in a large pan (if available, a cast iron skillet is ideal) until the oil just starts to smoke and an onion dropped into the oil immediately starts to sizzle.
Add onions and chicken thighs, skin side down with kitchen tongs (2 forks can be substituted for tongs if necessary.) This may have to be done in batches depending on the size of your pan or skillet.
Salt and pepper chicken generously in pan and cook for about 4 minutes or until the skin has turned a deep golden brown. Flip chicken over and cook 4 minutes on the other side, scraping up browned bits and moving onions around so that they don't get burned.
Place chicken and onions into pot with chicken stock, making sure to scrape up and add all the delicious browned bits and oil from the pan. Optional step: After adding chicken and onions to the pot of stock, pour 2 tbsps of Sherry or Marsala wine into the pan over medium heat. The alcohol will loosen any stuck on bits of chicken and onion but will evaporate quickly so it is important to immediately scrap up what comes loose and add everything in the pan to the pot.
Bring stock to a boil before turning down heat to medium low. The chicken will need to cook covered for a total of 50 minutes but other ingredients will be added at different stages during the total cooking time.
*Note: You will need to start adding other ingredients after chicken has cooked for 30 minutes so use this time to wash, peel, and chop vegetables.
Wash and chop carrots and celery into 3/4 pieces and set aside. Peel, scoop seeds out and chop butternut squash into 1 inch pieces. For tips on processing a butternut squash see below
*Note: To safely peel a butternut squash cut off both ends and slice the squash in half horizontally before attempting to peel. Stand on flat end and peel with a sharp pairing knife as shown in the photo.
When chicken has been in the pot cooking for 30 minutes add chopped carrots and celery and can of chopped tomato with juice.
Cook carrots and celery for 10 minutes before adding butternut squash.
Cook all veggies for another 10 minutes and then pull out chicken pieces and set aside to cool enough to handle.
Drain and rinse white beans and de-stem kale before adding to pot. Cook for 5 minutes stirring occasionally and then remove pot from heat.
Chicken should be cool enough to handle at this point. Remove and discard skin. Remove meat from bone, tear into bite size pieces, and add back to pot.
Optional: Set out fresh grated Romano or Parmesan cheese to sprinkle over each serving.