Make a simple tomato sauce. Warm the olive oil with the bay leaf, basil, parsley, onion, and garlic, and cook slowly for 3 to 4 minutes. Add the tomatoes, raise the heat to medium high, and cook until they are quite soft and broken apart, about 15 minutes. Pass them through a food mill; then return the sauce to the pan, and simmer until quite thick. If needed, add a pinch or two of sugar to balance the acidity, and season with salt and freshly ground black pepper. This should make 1½ cups.

While the sauce is cooking, bring 4½ cups water to a boil and add 1½ teaspoons salt. Whisk in the cornmeal in a stream so that lumps don't form, and when it has all been added, switch to a wooden spoon, lower the heat, and stir for 15 minutes. Pour it into a loaf pan or a 9-by-12-inch baking dish, and set it aside to cool. When it is thoroughly cool and firm, turn it out and slice it into pieces about ½ inch thick and about 3 inches long. If a loaf pan was used, cut the pieces again, diagonally.

Preheat the oven to 400°F. Lightly butter a gratin dish, and spread about 1 cup of the tomato sauce over the bottom. Arrange the polenta and the slices of Fontina in overlapping layers. Carefully spoon the remaining tomato sauce over the layers in a decorative way, leaving bands of red sauce between the yellow polenta and cheese. Crumble Gorgonzola over the top, pepper generously, and bake the gratin, uncovered, for 25 to 35 minutes. The cheese will melt into the tomato, making a sauce to spoon over the polenta. Garnish with the fresh herbs.