For the sauce, peel and chop the shallot and garlic. Heat 1 tablespoon of oil in a saucepan. Sauté the shallot and garlic for about 3 minutes. Drain the sardines in a sieve, add them and fry them briefly. Deglaze with wine and stock, bring to the boil and simmer for 4-5 minutes. Puree the sauce with a hand blender. Stir in capers and season to taste with salt, pepper and lemon juice. Keep sauce warm
Cover 3 slices of toast with 2 slices of mozzarella each. Place the slices on top of each other and finish with a 4th slice. Make 3 more stacks of bread mozzarella this way. Press all 4 stacks together slightly and cut off the edges of each stack
Whisk milk and eggs in a deep plate. Season with salt and pepper. Put the flour in a plate. Roll each stack in flour first. Then tap the flour lightly. Then pull through the milk and egg mixture. Heat 2 tablespoons of oil in a large frying pan. Fry the stacks for about 5 minutes, turning them over. Wash parsley and shake dry. Pluck off leaves and chop finely, except for a little bit for garnishing. Cut each stack of bread mozzarella diagonally in half and arrange on plates with some sauce, add the rest of the sauce. Sprinkle with chopped parsley and garnish with parsley leaves