Preheat oven to 400 degrees. Line two baking sheets with foil and spray lightly with vegetable spray.
Slice zucchini or squash into 1/4 inch-thick rounds. Toss rounds with oil, coating well.
In a wide bowl or plate, combine breadcrumbs, parmesan, salt and pepper.
Place rounds in parmesan-breadcrumb mixture, coating both sides of each round, pressing to adhere. The mixture will not completely cover each round, but provides a light coating on each side.
Place rounds in a single layer on baking sheets. Sprinkle any remaining breadcrumb mixture over the rounds.
Bake for about 22 to 27 minutes, until golden brown. (There is no need to flip them during baking -- they crisp up on both sides as is.)