Assemble sandwich with bread, sliced mozzarella, and anchovy fillet in the center.
Briefly soak both sides in milk. Dredge in flour, dip in beaten egg, then coat with bread crumbs. Chill 30 minutes to set the crust.
Heat olive oil in a skillet over medium. Pan‑fry sandwich until golden and crisp on both sides and the cheese is molten.
Drain on paper towel. Serve hot, garnished with halved cherry tomatoes and julienned basil.