Ready a pan of boiling water and add the potatoes. Cook until soft.
Once the potatoes are soft, drain the water and add the salt, pepper and butter. Mash the potatoes until smooth.
Ready a frying pan over a medium heat and add the oil, add the bacon then fry it until it becomes golden brown then add the onion and fry it until it becomes soft. Next remove it and let it cool down.
In a small frying pan add the panko and the vegetable oil, and use low heat to stir fry it evenly, until it becomes golden brown (you need to stir it often or some of them will be burn and some will not change colour), then let it cool down.
Add the bacon and the onion into the mashed potato and mix it well. Prepare heat the oven 210C. Then divide the mashed potato into 16 (if you prefer a bigger size you can just divide into 8). Add the mozzarella into mashed potato and roll it into small ball.
Once all finish, cover with plain flour ,egg and panko, put them into the oven cook around 15 to 20 minutes.
Enjoy your meal.