Cut mozzarella cheese into 12 sticks about 3 inches long and place them on a baking sheet lined with parchment paper. Freeze for at least 1 hour to prevent melting during frying.
Set up a breading station with three shallow bowls: place gluten-free flour in the first bowl; in the second bowl, whisk together eggs and water; in the third bowl, combine gluten-free breadcrumbs, garlic powder, dried Italian seasoning, salt, and black pepper.
Remove the frozen mozzarella sticks from the freezer. One at a time, dredge each stick in the gluten-free flour, shaking off excess.
Dip the floured stick into the egg mixture, coating completely.
Roll the stick in the breadcrumb mixture, pressing gently to adhere the crumbs. For extra crunch, repeat the egg dip and breadcrumb coating once more.
Place the breaded mozzarella sticks back on the parchment-lined baking sheet and freeze for another 30 minutes to firm up.
Heat vegetable oil in a deep skillet or pot to 350°F (175°C). The oil should be deep enough to fully submerge the mozzarella sticks.
Fry the mozzarella sticks in batches, carefully lowering them into the hot oil. Fry for 1 to 2 minutes or until golden brown and crispy. Do not overcrowd the pan.
Use a slotted spoon to remove the mozzarella sticks and place them on a plate lined with paper towels to drain excess oil.
Serve immediately with your favorite marinara sauce or dipping sauce.