Dice eggplant and sprinkle it generously with salt. Let sit in a colander for about 30 minutes. After 30 minutes, rinse eggplant and pat it dry.
Pre-heat oven to 350 degrees.
Heat a large skillet over medium heat. Add ¼ C olive oil and once oil is shimmering, add eggplant. Fry the eggplant for about 8 minutes, stirring occasionally. Remove eggplant from pan with slotted spoon to paper towel lined plate.
Add carrots and celery to skillet and cook for about 3 minutes. If you find yourself needing a little more oil, add it here.
Add in garlic and onion and cook for another 5 minutes. Stir in orzo and tomato paste and cook for 2 minutes.
Take the skillet off the heat and add in oregano, lemon zest, mozzarella, parmesan, tomatoes, eggplant, lemon zest, and some salt and pepper. Pour in the vegetable stock and stir well.
Put mixture in an 8×11 baking dish, cover in foil, and put it in the oven at for about 40 minutes, 20 minutes with the foil covering the dish and 20 minutes with the foil removed.