Start by peeling and grating the potato.
Transfer this grated potato to a bowl, add enough cold water to cover it, mix and set aside.
In another bowl, add the ground beef, the grated onion, the grated potato fully drained, the egg, the salt, the black pepper and mix all the ingredients together very well.
Cover with a plastic bag touching the meat, and let it rest for 30 minutes.
Meanwhile, in an ovenproof dish, add 1 drizzle of vegetable oil and spread well.
Once the meat has rested, remove the plastic bag and split it in 4 equal-sized portions.
Get one of these portions and shape it into a patty, just like shown in the video.
Transfer these patties to the dish we greased.
Using a spoon, make a hole in the center of each patty.
Take them to a preheated oven at 200°C (392°F) and roast them for 30 minutes.
After this indicated time, remove from the oven, sprinkle the grated mozzarella cheese all over them, and place one whole egg on each patty.
Take these patties back to the oven and roast them for another 15 minutes.
Serve.