Instructions

• Place the peeled, evenly cut 2 pounds russet potatoes in a large pot and cover with cold water. Bring to a boil over high heat, then lower the heat and simmer about 20 minutes, until a fork easily pierces the potatoes.
• Drain the potatoes and return them to the pot. Place the pot over low heat and gently shake it for 1–2 minutes to evaporate excess moisture.
• Transfer the potatoes to a bowl. Add 1 tablespoon unsalted butter, 1/4 teaspoon of the 1/2 teaspoon salt (reserved), and 1/8 teaspoon of the 1/4 teaspoon freshly ground black pepper (reserved). Mash until mostly smooth but still a bit chunky. Set aside.
• Heat a skillet over medium heat and add 2 teaspoons neutral oil. Add the finely chopped medium yellow onion and cook, stirring occasionally, until soft and lightly browned, about 8 minutes.
• Add the 16 ounces lean ground beef to the skillet with the onion. Season with the remaining 1/4 teaspoon salt and the remaining 1/8 teaspoon black pepper. Break up the meat and cook, stirring, until no pink remains. Remove from heat and let the meat-and-onion mixture cool slightly (2–3 minutes).
• Fold the cooked meat and onions into the mashed potatoes. Mix gently until evenly combined.
• Divide the mixture into 8 equal portions. Shape each portion into an oval patty about 3 inches long. Place the patties on a tray and chill in the refrigerator for 15 minutes to firm up.
• While the patties chill, set up three shallow bowls: one with 1/2 cup all-purpose flour, one with the 2 beaten eggs, and one with 1 2/3 cups panko breadcrumbs.
• Dredge each chilled patty first in the flour (shake off excess), then dip in the beaten eggs, and finally coat evenly with panko, pressing gently so the breadcrumbs adhere. Repeat for all patties.
• Pour oil for deep-frying into a deep pot to a depth of about 2 inches and heat to 350°F. Fry the patties in small batches (do not overcrowd) about 2–3 minutes per side, until the exterior is golden brown and crisp.
• Remove the fried korokke with a slotted spoon and drain on paper towels. Keep warm while you finish frying the remaining batches.
• Serve the hot korokke with tonkatsu sauce on the side for dipping.