Saute the onions in the bacon fat (or olive oil) until tender and almost starting to brown. I saute mine in the pot that goes into the thermal cooker.
Add all the other ingredients and bring them back to a boil.
Reduce the heat a little and simmer for 15 – 20 minutes. Make sure the pot is boiling and the bubbles can’t be stirred down. The vegetables need to be heated all the way through.
Remove from heat. Place the lid on the thermal cooker pot and place it into the thermal cooker.
Leave the food in the cooker for 4-5 hours. Do not check the food since that will release the heat. Keeping the heat in the pot is needed for thermal cooking.
After 4-5 hours the soup will be ready. Carefully remove the cooking pot from the cooker and enjoy!