Cut the fresh mozzarella block into 3/4-inch thick sticks, about 3 inches long. Place the sticks on a baking sheet lined with parchment paper and freeze for at least 1 hour to prevent melting during frying.
In a shallow bowl, place the all-purpose flour.
In a second shallow bowl, whisk together the eggs and water until well combined.
In a third shallow bowl, combine the Italian-style breadcrumbs, garlic powder, dried oregano, salt, and black pepper.
Remove the frozen mozzarella sticks from the freezer. Dredge each stick first in the flour, shaking off excess, then dip into the egg mixture, and finally coat thoroughly with the breadcrumb mixture. For an extra crispy coating, repeat the egg and breadcrumb coating once more on each stick.
Place the coated mozzarella sticks back on the parchment-lined baking sheet and freeze for another 30 minutes to set the coating.
Heat vegetable oil in a deep frying pan or pot to 350°F (175°C). The oil should be deep enough to fully submerge the sticks.
Fry the mozzarella sticks in batches, about 2-3 minutes per batch, until golden brown and crispy. Do not overcrowd the pan.
Using a slotted spoon, remove the mozzarella sticks and place them on a paper towel-lined plate to drain excess oil.
Serve immediately with warm marinara sauce for dipping.