Cut cheese sticks into thirds. Place flour on a plate and season it with salt and pepper. Put the egg in a small bowl. Place bread crumbs on a plate.
Add cheese pieces to flour and toss to coat. Dip in egg, and then roll in bread crumbs. Arrange breaded cheese in a single layer on a tray or baking sheet. Let stand for 15 to 30 minutes. Pour oil into large skillet to a depth of 1-inch, and heat over medium-high heat. When oil is hot, carefully drop cheese pieces in, a few at a time, and fry until golden, about 30 seconds. Remove from oil with a slotted spoon and drain on paper towels. Serve with your favorite chunky marinara sauce for dipping.