Unwrap the string cheese sticks and cut each in half to make 24 pieces. Place them in the freezer for 1 hour until firm.

Prepare three bowls: one with flour, one with beaten eggs mixed with milk, and one with breadcrumbs, garlic powder, onion powder, black pepper, and salt.

Dredge each frozen cheese stick in flour, then dip in the egg mixture, and finally coat with breadcrumbs. For extra crispiness, repeat the egg and breadcrumb step once more.

Return the coated sticks to the freezer for another 30 minutes to help them hold their shape during frying.

Heat 2 inches of vegetable oil in a deep saucepan to 350°F (175°C).

Fry the mozzarella sticks in small batches for 2–3 minutes, or until golden brown and crispy.

Drain on a paper towel-lined plate. Serve immediately with warm marinara sauce.