Cut each mozzarella stick in half to yield 24 pieces. Place cheese pieces in the freezer until frozen.
In a small bowl, whisk the egg. Place the flour in a separate shallow dish.
In another bowl, combine Italian seasoned breadcrumbs, panko crumbs, parmesan cheese, and dried parsley.
Dip frozen mozzarella pieces into flour, shaking off excess, then into the beaten egg, and finally coat with breadcrumb mixture.
Repeat coating process with all pieces and place them on a tray lined with wax paper.
Freeze the breaded mozzarella bites for at least 1 hour to prevent melting while baking.
Preheat oven to 400°F (204°C). Line a baking sheet with foil and lightly spray with olive oil cooking spray.
Arrange frozen mozzarella bites on the prepared baking sheet. Spray tops lightly with olive oil.
Bake on the bottom third of the oven for 4 to 5 minutes until golden and crisp, then carefully turn and bake for another 4 to 5 minutes, watching closely to avoid melting.
Notes
Keep frozen bites stored in the freezer to bake fresh whenever you need a quick snack. Serve with marinara sauce for dipping.