Preheat oven to 400 degrees. Line a large rimmed baking sheet with parchment paper or tin foil with baking spray. Set aside.

Cut each zucchini into halves through the length so each half will sit flat on the baking sheet. Take a small spoon and scrape out the middle of the zucchini from one end to the other. Create a valley for the toppings to sit in. Focus on removing the seeds and pulp. Place on prepared baking sheet. In a bowl, stir together olive oil and garlic then brush lightly over tops of zucchini. Sprinkle with salt and pepper to taste. Next, spread marinara sauce over each zucchini. Sprinkle tops with mozzarella cheese and then parmesan. Top with pepperoni slices (placing them near the center as the cheese can melt and spread). Bake in preheated oven 12 - 18 minutes (bake time will vary depending on how thick your zucchini are and how crisp/tender you want them).

Remove from oven and sprinkle with chopped fresh oregano or italian spices if desired. Serve warm.