Begin by preparing your sauce: Heat up a large skillet to medium high heat and add olive oil. Saute the onion and pepper until the onions are clear and fragrant (about 5 minutes). Turn down the heat to medium and add the mushrooms. Once the mushrooms are browned and smaller (about 5 minutes), add the tomatoes and cover. Simmer for around 10-15 minutes until the tomatoes have popped, and can be smashed with a spoon or spatula. Add in 1 cup crushed tomatoes and turn heat to low. Stir and let simmer until ready your casserole is ready.

Prepare your grill. While grill is being heated, prepare your eggplant. Slice them vertically, and brush with olive oil and salt. Grill the eggplant on each side until opaque. Remove and set aside.

Assemble the dish: Heat up your oven to 400 degrees. Grease a 9x13 inch casserole dish. Begin with a cup of sauce on the bottom, layer with 1/3 of the eggplant, add another cup of sauce, add some fresh basil, and finally top with 1/3 cup mozzarella and 1/3 cup parmesan. Repeat for 2 more layers.

Bake for 15 minutes or until the top is golden brown and bubbly.

Remove and set aside for 10 minutes before serving.