Place oven rack 6 inches from broiler and preheat the broiler (High).
Lightly spray rimmed baking pan with olive oil spray. Place zucchini slices on pan, flip to coat both sides with oil. Sprinkle lightly with Italian seasoning.
Place under the broiler for 4 minutes. Remove pan from oven and flip each slice over.
Top each slice with sauce (about ½ teaspoon), mozzarella cheese, one pepperoni slice, and Parmesan cheese.
Return zucchini to oven and broil for 1 to 2 minutes or until pepperoni is slightly crisp and cheese is melted.
Let cool 2 to 3 minutes before serving.
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Notes
Yield will vary depending on size of zucchini and how thick you slice them.
If you prefer, omit the pepperoni and make cheese pizzas. Other toppings of your choice can be substituted for the pepperoni.
Zucchini pizza bites are best eaten fresh. If you have any left over, refrigerate them in a single layer, covered with plastic wrap, for up to 3 days. Reheat them in the microwave or bake them in your toaster oven until heated through.