Step 1

Position rack in center of oven; preheat broiler to High. Coat a large rimmed baking sheet with cooking spray.

Step 2

Whisk egg whites in a medium bowl until well combined. Add zucchini and toss to coat well.

Step 3

Combine panko, Parmesan, Italian seasoning, onion powder, salt and pepper in a shallow dish. Working in batches, toss the egg-coated zucchini in the panko mixture, pressing both sides to adhere. Arrange the zucchini on the prepared baking sheet. Coat the tops with cooking spray. Broil until golden and crispy, 3 to 4 minutes per side. Serve with your favorite sauce, if desired.