Mix the panko, bread crumbs, Italian seasoning, salt, garlic powder, and pepper in a bowl. In a separate bowl, whisk the eggs and water together. Place flour in a third bowl. Place bowls side by side starting with flour, then egg, then bread crumbs.
Prepare a tray lined with parchment paper and set this next to the bowl with the bread crumb mixture.
Use tongs to place each mozzarella stick into the flour mixture (cover completely), then dip it into the egg mixture, then completely cover it with the bread crumb mixture and set onto prepared tray.
When all of the mozzarella sticks have had one coat of breading we are going to give them a second coating. This time, flour is not needed. Once again, using tongs, place each cheese stick in the egg mixture and then coat completely with the breadcrumb mixture (sides and ends as well). Place back onto the tray.
Freeze the coated mozzarella sticks for at least 1 hour.
Heat oil in a heavy skillet, or dutch oven, to a temperature of 325-350 degrees. A thermometer is extremely helpful. Place a plate lined with paper towels next to the deep frying station, this will be used to transfer the cheese sticks to when they come out of the oil.
Fry mozzarella sticks for a minute or 2 per side, or until golden brown. Do not crowd the pan as it will drop the temperature of the oil. Pay close attention to how quickly they are browning and adjust your temperature if needed.
Remove mozzarella sticks from oil and place on prepared plate lined with paper towels. Serve with marinara sauce or ranch dressing on the side if desired.