Trim the root ends off of the leeks and all but 1 or 2 inches of the green leaves. Slit them down the middle and cut them into fourths lengthwise. Rinse well and cut into ¼ inch slices.
Melt butter in a saucepan, add the leeks and water, then cover and simmer for about 10 minutes. Remove the lid, raise the heat slightly, and cook until the liquid has evaporated.
Add the Herb Pancetta, tomatoes, provolone and parsley, stir and set aside.
Bring 2 cups of water and salt to a boil in a heavy saucepan.
In a separate bowl, mix the remaining cup of water with the polenta and stir until well-combined.
Add the polenta to the saucepan, being careful to stir constantly to avoid lumps. Lower the heat to a simmer, then cover and continue to cook, stirring occasionally. Allow it to cook for at least 20 minutes, or until the polenta is thick and pulling away from the sides of the pan.
Remove from heat, add the leek mixture and pepper to taste.
Sprinkle water in a glass baking dish, 8 1/2X11 inches. Spoon in the polenta. The mixture should be thick enough to hold its shape. Smooth it with a knife to a depth of about ½ inch. Let the mixture cool, cover it with plastic wrap, and refrigerate. It will keep for at least two days refrigerated.
When ready to serve, cut it into 2-inch squares, sprinkle with Parmesan, and broil until hot.
The uncooked polenta squares may be frozen until ready to use. Thaw before broiling.