Prepare the Potatoes: Boil the Yukon Gold potatoes until fork-tender, then mash them.
Make Potato Mixture: To the mashed potatoes, add 1 teaspoon of salt and 5 tablespoons of flour. Mix until combined.
Prepare the Batter: In a separate bowl, whip 2 eggs with a pinch of salt. Add 1/2 cup of milk and gradually mix in 1 cup of flour to avoid lumps.
Form the Balls: Take a portion of the potato mixture, flatten it, place a cube of mozzarella cheese in the center, and enclose the cheese with the potato mixture to form a ball.
Coat the Balls: Dip each ball first into the batter, then roll them in breadcrumbs to coat evenly.
Fry the Balls: Heat peanut oil to 350°F (175°C) and deep-fry the balls until they are golden brown and crispy.
Serve: Serve the cheesy potato balls hot, ideally with a dipping sauce of your choice.