Bring 6 cups of water to a boil in large heavy bottomed saucepan or Dutch oven. Add the salt. Followed by the polenta in a slow steady stream; whisking the mixture as you go. Reduce the heat to low and continue stirring for several minutes until there are no lumps. Simmer the polenta for 30-40 minutes stirring occasionally so that the polenta will not stick.
Remove the polenta from the heat and add the butter in 3 additions, stirring until well incorporated between additions.
Heat 2 tablespoons of olive oil in a saucepan over medium heat. Add two garlic cloves that have been thinly sliced. Cook these gently until just beginning to brown.
Add one 14.5 oz can of diced tomatoes and a little salt. Go gently on the salt because some brands of tomatoes are too salty to begin with. Add about 1 tablespoon of fresh oregano leaves. Turn the heat to very low and simmer about 1/2 hour, until reduced to a sauce consistency.
Lightly oil the tops and sides of a shallow 9x13 inch baking dish. Using the back of a spoon spread about 1/2 of the polenta all over the bottom. Crumble and dollop about 5 ounces Gorgonzola and 5 ounces of Taleggio evenly across the surface of the polenta layer.
Add the rest of the polenta spreading it over the cheese with the back of a spoon or an off set spatula. Work carefully to assure that the cheese is completely covered. Lay a piece of plastic wrap over the top layer of polenta, using the palms of your hands compact the polenta as evenly and firmly as possible.
The polenta may be made ahead up to 24 hours in advance to this point, left covered and refrigerated. In fact it makes the polenta firmer and is easier to cut after baking.
When you are ready to bake the polenta. Pre-heat the oven to 350 degrees F. Remove the plastic wrap. Pour the prepared tomato sauce over the top of the polenta and sprinkle 1/2 cup grated Parmesan cheese over the top.
Bake the polenta for 30 minutes until it is browned and bubbly.
Remove the polenta to cool on a wire rack for about 1/2 hour. It should firm up as it cools.
To serve slice the baked polenta into serving-sized portions and serve alongside an arugula salad. The first piece may be difficult to remove from the tray neatly. You may want to set it aside as a post party treat for the cook. But the other slices should come out easier.
A perfect baked polenta will hold its shape, but oh so barely. It may sag a bit under it’s own weight and it will ooze plenty of cheese all over the plate.