01 -
Cut peeled potatoes into quarters and boil them in water until soft, about 20-25 minutes. Drain properly, put back in the pot while still warm, and mash them smooth. Stir in butter until it melts, then let them sit.
02 -
Warm oil in a skillet on medium heat. Cook finely chopped onion for 3-4 minutes until soft. Toss in the ground beef, breaking it up while it cooks. Mix in soy sauce, sugar, and black pepper. Cook everything a few more minutes until the beef's browned.
03 -
Mix the mashed potatoes with the cooked beef and stir well. Taste and add salt and pepper as needed. Cool it down enough so handling it is easy.
04 -
Form the mix into ovals about 3 inches long and 1 inch thick. Lay them on a baking sheet, cover up with plastic, and chill in the fridge for half an hour or more to firm them.
05 -
Set up 3 plates: one for flour, a second with whisked eggs, and the third with panko crumbs. Dip each patty into the flour, then into eggs, and finally cover them in the panko.
06 -
In a saucepan, heat 1½ inches of oil to 340°F. Fry a few patties at a time for about 3 minutes. Flip them over midway through. Once golden brown, remove them and let them drain on a rack or paper towels.