Peel and chop about two pounds of Russet potatoes into uniform pieces. Boil in a large pot of salted water for 15–20 minutes or until fork-tender. Drain and return to the pot, then mash with 4 tablespoons of butter and ½ cup of cheese until creamy and smooth, allowing them to cool slightly before moving to the next step.

Once the mashed potatoes are cool enough to handle, scoop out a generous tablespoon of the mixture and roll it into a ball about the size of a golf ball. Place the formed balls on a parchment-lined tray, ensuring they are evenly spaced.

In one bowl, beat two eggs with a splash of water to create an egg wash. In another bowl, pour in 1 cup of breadcrumbs. Dip each potato ball into the egg wash, ensuring full coverage, and then roll in the breadcrumbs until well-coated.

In a large, deep skillet or pot, pour in enough oil to submerge the potato balls about halfway. Heat the oil to 350°F (175°C). When the oil is shimmering, carefully drop the potato balls into the hot oil in batches.

Fry for about 3–4 minutes, or until they reach a beautiful golden brown color. Use a slotted spoon to gently turn them halfway through cooking for even browning.

Transfer them to a plate lined with paper towels to drain any excess oil. These crispy fried mashed potato balls are best served hot.