2 tablespoons extra-virgin olive oil
5 garlic cloves, chopped
4 anchovy fillets
3 tablespoons tiny capers in brine, drained
2 tablespoons unsalted butter
½ cup dry white wine
3 tablespoons lemon juice
8 slices firm white bread, crusts removed
12 ounces fresh mozzarella, thinly sliced
all-purpose flour, for dredging
2 large eggs
2 tablespoons milk
vegetable oil, for frying
1 tablespoon chopped fresh Italian parsley
NOTE: a variation suggest by Lidia – add a whole anchovy to the sandwich inside with the sliced mozzarella.
Make the sauce: Pour the olive oil into a large skillet set over medium-high heat. When the olive oil is hot, add the chopped garlic. Cook and stir until garlic is sizzling and fragrant, taking care not to burn it. Add the anchovies and capers and stir until capers dissolve into the oil. Add the butter. When the butter is melted, pour in the white wine and lemon juice. Bring to a rapid simmer and cook until reduced by half, about 6 to 7 minutes. Keep warm.
Lay 4 slices of bread on your work surface. Top with the sliced mozzarella, making sure the mozzarella does not extend over the edges of the bread, trimming to fit if necessary. Top with remaining bread to make 4 sandwiches. Seal each sandwich at each corner with a toothpick (4 picks per sandwich).
Spread flour on a rimmed plate. Beat eggs and milk together in a wide, shallow bowl. Heat about 1/2-inch vegetable oil in a skillet over medium heat, oil is ready when a crust of bread sizzles on contact.
Dredge sandwiches well in flour, making sure to coat all sides and tap off the excess. Soak the sandwiches on all sides on the eggs, letting the excess drip back into the bowl. Carefully ease the sandwiches into the oil and fry until golden brown on both sides and cheese is melted, about 1 to 2 minutes per side. Drain well on paper towels. Remove the toothpicks and use a serrated knife to cut them in half on the diagonal.
Return the sauce to a simmer, stir in parsley. Spread sauce on 4 serving plates, top each with and sandwich and serve hot.