Beat the milk and eggs.  This makes a custard for the bread.In another bowl mix the bread crumbs with some salt and pepper and stir. Put the tuna in a bowl and add the celery,mayonnaise, relish, lemon juice, salt and pepper. You can add anything into the tuna; sometimes I add chopped shallots, dried cranberries, celery or anything that adds crunch.

Now you are ready to assemble.  Top two slices of bread with some tuna mixture.On top of this spread the shredded mozzarella and pat it down.  Top with the remaining bread slices and pat down gently. You can also add your favourite mustard to the bread or smear each inside slice with butter.

Dip both sides and all the edges of the sandwich into the custard mixture and then into the Panko bread crumbs. The magic happens when you dip the bread into the Panko crumbs. Put the sandwiches on a plate and refrigerate to firm them up. This is the secret.

Place a pan of medium heat and add the olive oil.  You will know when it is ready by dropping in a few bread crumbs.  If they bubble away, put in your sandwiches.

Cook until golden brown and place on paper towels to drain.  Season with a bit more salt and pepper.