Trim bread crusts and assemble sandwiches: 1 bread slice, 1 mozzarella slice, 1 ham slice (folded to fit inside the edges of the bread), then another mozzarella slice and bread slice. Pinch the sandwich edges to seal.
In a shallow bowl, season the flour with the granulated garlic and onion.
In a medium bowl, beat the eggs with the cheese, lemon juice, and salt and pepper.
In a large skillet, heat a shallow layer of EVOO, 3 to 4 turns of the pan, over medium. Dredge the sandwiches in the flour mixture, then coat in the egg batter. Fry two at a time, turning occasionally, until deeply golden, 6 to 7 minutes (add more oil for second batch, if necessary). Cut diagonally and serve.