Preheat oven to 350 degrees F. Lightly coat a 2-quart rectangular baking dish with cooking spray; set aside.
In an extra-large skillet heat 1 tablespoon of the oil over medium-high heat. Add eggplant; cook for 5 to 6 minutes or until tender and lightly browned, stirring occasionally. Transfer to a large bowl. Add the remaining 1 tablespoon oil to skillet. Add sweet peppers, mushrooms, onion, celery, and olives. Cook about 10 minutes or until onion is tender and liquid is evaporated, stirring occasionally. Transfer to bowl with eggplant. Drain off any liquid.
Transfer cooked vegetables to the prepared baking dish. Top with half of the pasta sauce. In a medium bowl combine egg, ricotta cheese, Asiago cheese, the 1/4 cup parsley, the Italian seasoning, and garlic powder. Spoon ricotta mixture in mounds on top of pasta sauce in dish. Top with the remaining pasta sauce.
Bake, uncovered, for 30 minutes. Top with provolone cheese. Bake, uncovered, for 10 to 15 minutes more or until mixture is bubbly and cheese is melted. If desired, sprinkle with pine nuts and additional parsley. Let stand for 5 minutes before serving (casserole will be saucy).