Prepare three separate bowls for dredging your mozzarella sticks. One bowl of buttermilk, egg, and cayenne pepper, lightly whisked together. Second bowl of all-purpose flour. Third bowl of Panko crumbs and Italian Seasoning mixture.
Dip cheese sticks into buttermilk mixture, then into all-purpose flour, then back into the buttermilk mixture and then finally into the Panko crumbs. Set aside on a sheet pan until all cheese sticks are prepared and the oil is ready for frying.
Pour oil into 12-inch skillet to about 2 inches deep over medium heat. Once oil begins to shimmer and reaches about 350 degrees F, it is ready to add the cheese sticks in batches. Fry a few cheese sticks at a time, removing with tongs as soon as they become brown. Watch carefully as they will overcook quickly.
Remove to a kitchen sheet pan lined with paper towels to drain. Then, serve warm.