Start by dicing your yellow onion, carrot, and celery. Cut the russet potato into 1-inch cubes and slice the chicken sausage into bite-sized pieces. Having everything prepared makes the cooking process seamless.
In your slow cooker, add the diced onion, carrot, celery, and potato. Follow with the sliced chicken sausage.
Pour in the low-sodium chicken broth and skim milk. This will create a rich base for your soup.
Use a wooden spoon to stir the ingredients until well mixed. Set your slow cooker to low and let it cook for 6-8 hours or high for 3-4 hours.
About 15 minutes before serving, stir in the chopped baby spinach. This will wilt down perfectly and add a lovely green touch to the soup.
Once the cooking time is up, give the soup a final stir and taste for seasoning before serving. Ladle the warm soup into bowls and enjoy the hearty flavors with a slice of crusty bread on the side.
