Preheat oven to 400 degrees. Coat a 9-inch springform pan with cooking spray.
In a large microwave bowl, add zucchini, onions and garlic. Drizzle 1 teaspoon olive oil over the top. Microwave for about 4-5 minutes until the vegetables are soft. Season with a little salt and pepper.
Coat a baking sheet with cooking spray. Add peppers and eggplant to the pan. Drizzle 2 tablespoons olive oil over vegetables. Toss well to coat. Spread out vegetables over the entire pan.
Place in oven and roast for 30-40 minutes until soft but not browned. Remove from oven.
Place each vegetable in a single overlapping layer. Begin with half the eggplant and next, add all the red peppers. Sprinkle with half the cheese and a little salt and pepper. Add all the zucchini and onions. Next, the yellows peppers. Sprinkle with remaining cheese and a little salt and pepper. Finally add the remaining eggplant.
Cover the top of the vegetables with a 9-inch round piece of parchment paper or waxed paper. Place another cake bottom, cake pan or plate on top and weight it down with a few heavy cans or jars (over time the weight holds this torte together).
Place on a larger plate or baking sheet (it will leak) and refrigerate for several hours or overnight.
Before serving, place on a platter or cake plate and serve at room temperature or place in the microwave to warm.