Heat the oil in a soup pot. Remove the sausage from the casing, add to the pot, break up the sausage with a spatula and fry until golden on the outside and cooked all the way through, then remove to a separate plate. (If your sausage is very fatty, remove the excess fat but leave 2 tbsp in the pot)
To the same pot, add the chopped onion, celery and sliced carrot and cook for 10 minutes over low heat, then add minced garlic, basil, oregano and thyme, cook for 30 seconds longer.
Add the drained canned beans, peeled and diced potatoes, a bay leaf and bring the sausage back to the pot.
Then top with the chicken stock, bring to a boil, then lower the heat and simmer for 30 minutes. At the end the potatoes should be soft. If you want to make the soup thicker, remove 1/3 of the beans and potatoes from the pot and blend them into a paste in a blender, then add back to the soup and stir. Or you can skip this step to make it simpler.
Now add the kale and cook for 5 minutes longer. Taste and add more salt if needed.
At this point you can serve the soup or you can add 1/2 cup of single cream (light cream) if you desire and warm it through. Both versions taste delicious!