Preheat oven to 350 degrees F. Wash and slice egplant into slices 1/4 inch thick and spread on platter. Sprinkle slices with salt and let stand for one hour to draw out bitter juices. Pat slices dry with paper towel, dip in beaten egg and dredge through breadcrumbs. Fry in hot oil until brown on both sides and drain on paper towel.
In the bottom of the baking dish, spoon a small amount of the spaghetti sauce and spread it around. Layer the eggplant,sauce,mozzarella,provolone and parmesan. Top parmesan with sauce and bake for 45 minutes to an hour, until all is hot, melted and bubbly.
The eggplant in ready at this point to be served as a main dish, but we are taking it to the sandwich level.
Slice each section on Italian bread down the middle and spread open, being careful not to separate it. Place eggplant over bread, top with 2 slices of provolone and place under broiler until bread is toasted and cheese is melted.
