Dice chicken breast and onion.
Heat olive oil in a large saucepan or dutch oven over medium-high heat.
Add chicken and onion and cook for 5-8 minutes or until onion is transparent and chicken is cooked through.
While chicken and onion are cooking, remove stems from spinach and rinse well.
Coarsely chop spinach.
Add stock to dutch oven and raise heat to high and bring to a boil.
Add the tortellini and return to a boil, then reduce heat to a simmer.
Cook for 5-6 minutes until tortellini floats and is cooked through.
Fold in spinach until it is all wilted in the soup.
Season with sea salt and fresh cracked pepper to taste.
Take off heat and serve topped with grated parm cheese and a crusty whole grain french baguette.