There are a few rules with this dish - when it comes to the mozzarella, buffalo is preferred. It is a richer cheese and doesn't leech liquid as it cooks which means it won't turn the bread to mush. When it comes to the use of anchovies, that seems to be a matter of preference - looking at Artusi's recipe from 1891 it only uses mozzarella. While you will see square and triangular versions, round are preferred as this resembles the wheels of a carriage - after all, the dish is called mozzarella in a carriage.
For my interpretation, I'm sticking with buffalo mozzarella having sourced it straight from the burrata man. I've topped the slices of mozzarella with fresh basil and then wrapped it all in a paper thin slice of prosciutto. Finally, rather than frying it in oil, I've cooked them in butter.
6 slices pane in cassetta or pane carré
buffalo mozzarella cut into ½ cm thick slice
fresh basil leaves
3 slices prosciutto
flour, for dusting
freshly ground sea salt
butter, for cooking
First up you need to remove the crusts from your bread and I've taken the easy way and just stamped out a circle from the centers of each slice - there's hardly any waste doing it this way.
Next step is to make the mozzarella parcels. Cut the cheese so it's just a little bit smaller than the bread - place the cheese on a slice of prosciutto, top with a little ripped basil and then roll form a package. If you've got an extra long slice of prosciutto don't be tempted to keep rolling, you just want one layer of prosciutto to surround the mozzarella.
Place this parcel in the center of the bread, top with another slice of bread and then press down around the edges - the bread is soft so it should stick together.
Once you've made all the sandwiches, give them a good dusting of flour making sure you also coat the edges.
In a bowl, add the egg, a pinch of salt and half a eggshell of milk - whisk with a fork until combined.
Dip the sandwich into the egg mixture, make sure you turn it around and then turn it on its side to soak the edges. Place this on a tray while you complete the process for the remaining sandwiches. If there is any egg left over, drizzle it over the sandwiches.
Place a generous knob of butter in a non-stick skillet and bring it up to temperature over a medium heat - when the butter has melted and is starting to sizzle, carefully place the sandwiches into the pan - use a wide spatula to help move it into the pan. Lower the heat a little and let them cook until the undersides are golden before turning them over.
When both sides are golden remove them from the pan and serve at once.
To complete the dish, I've served these with a simple salad of mâche (lamb's lettuce) and tomatoes.