In a bowl, add the flour, milk, melted butter and salt. Start mixing it until it's kind of lumpy.
Start kneading it for approximately 5 minutes.
Cover it with plastic wrap and leave it in the fridge for 1 hour.
Meanwhile, in a bowl, mash a peeled boiled potato and add the mayo and mix it well.
Take out the dough from the fridge and flatten it into a round shape.
Add in a lot of mozzarella and then the potato mixture on top of it.
Wrap it up and make sure it is well sealed.
Start rolling again until it's flattened.
In a well heated pan, add some butter and add the bread. Flip when golden.
After flipping, spread some extra melted butter on the other side.
When both sides are golden, serve while warm.
