After much testing of this recipe over the years, I finally decided that 3 tablespoons of cornflour gives you the perfect thickness. If you’d prefer your soup to be more like a hearty chowder or casserole, just add a tablespoon or two more of cornflour.  If you'd prefer a much thinner soup, simply reduce the cornflour to just 2 tablespoons. The soup is lovely heated up the next day, but I sometimes find some of the liquid is soaked up by the gnocchi in the fridge. Simply add a bit of water to thin it out again to your liking.