Cook the bacon until the fat is rendered, discard all fat but 2 tbsp. To the same pot with bacon add chopped onions, carrots and celery and thyme and sauté over low heat for 5 minutes, then add garlic and cook for 30 seconds longer.
Pour in the chicken stock, stir to combine. Add the chicken breasts and a pinch of salt,cook for 30-35 minutes, then take the chicken out, shred and return back to the pot. Add the gnocchi and kale or spinach. Cook for 3 minutes, then add in the cream.
To make the roux, which will thicken the soup, mix the melted butter with flour, then stir into the soup, allow it to simmer for a couple of minutes until the soup thickens. Season with salt to taste.