In a heavy copper plat à sauter or a large, low-sided earthenware receptacle large enough to hold the squid and leeks gently packed in a single layer, stew the leeks, salted, in the oil for 10 minutes or so, turning them carefully so as not to damage them, remove them from the pan, and put them aside. Sauté the squid in the same oil, over a higher flame, salted, for several minutes, until the liquid they exude has been almost entirely evaporated, sprinkle over the flour, stir, and cook for another minute or so, add the seasoning, herbs, and garlic, and, stirring all the while, slowly add the red wine, then the water. Bring to a boil, gently slip the leek sections back into the pan, one by one, easing each into place between squid sections. Cook, covered, at a bare simmer, for something over 1½ hours—the sauce should be consistent and the squid and leeks of a melting tenderness, but absolutely intact. Scatter the surface with the croutons and chopped parsley at the moment of serving (in the cooking utensil).