Preheat oven to 425 degrees F. Line a baking sheet with parchment paper or a silpat mat and lightly spray with nonstick spray.
Grate zucchinis and place them in a kitchen towel or multiple sturdy paper towels. Be sure to ring out as much water as you can and do it over a colander just incase any break out of the paper towels. Ring out the excess water and place grated zucchini in a large mixing bowl.
To the mixing bowl, add egg, 1 1/2 cup mozzarella cheese, parmesan cheese, garlic powder, oregano, and salt. Mix with a wooden spoon until all of the ingredients are combined together.
Dump the zucchini mixture onto prepared baking sheet and spread out with spatula. Form an approximately 12 inch by 8 inch rectangle using the spatula to shape the mixture. The mixture should be about 1/4 inch thick.
Sprinkle the remaining 1/2 cup of mozzarella cheese on top and bake for 15 minutes or until the cheese is melted and bubbly. Slice and serve immediately.