Brown the onion and garlic in a small amount of olive oil in a medium sized stock pot.
Add chicken stock, water and salt to taste. Bring to a boil and simmer.
Brown chicken sausages in a separate frying pan and cut into chunks. Set aside.
Add chopped escarole or spinach and cannellini beans to the stock mixture. Let simmer for 5–10 minutes.
Add the sausage right before serving. Top with fresh parsley and lemon zest.