Over medium high heat saute the garlic until golden brown then remove and discard. Add your onion, salt and pepper and saute until tender. Add both cans of tomatoes. Using a potato masher, crush the tomatoes. Lower the heat and let the sauce simmer for 20-25 minutes.
Preheat your oven to 400F. Place your sliced eggplant into a colander and salt each disc. Let the eggplant sit for at least ½ an hour. Using a paper towel, wipe the moisture off the eggplant and place them onto a parchment paper lined baking sheet. Roast the eggplant for 10 to 15 minutes on each side.
Preheat oven to 450F. Grease and 8x10 baking dish with butter. Add a thin layer of sauce to the bottom. Then start to layer, eggplant, sauce, ⅓ C grated parm REPEAT. Somewhere in the middle add one layer of fresh mozzarella then continue to layer until you run out of eggplant. You should end with a heavy layer of grated parm. Bake for 15min. If necessary broil for 2-3 minutes.
