In a small bowl, whisk together the egg with a tablespoon of water. In a medium bowl or plate, mix together the breadcrumbs, panko breadcrumbs, grated parmesan, paprika, garlic powder, salt and pepper.
Pat the zucchini rounds dry with a paper towel to remove excess moisture. Dip them each in the egg wash, then in the breadcrumb mixture to coat completely on both sides. Place on the prepared baking sheet(s).