Peel and dice 2–3 starchy potatoes into uniform chunks, then boil for about 10 minutes until tender. Drain and cool.

Heat a tablespoon of olive oil in a skillet. Cook 1 pound of ground beef until browned, add half an onion and one carrot, and sauté until soft.

Mash the cooled potatoes until smooth and mix with the beef and vegetable filling. Set aside.

Shape the potato mixture into 8 oval croquettes, roughly 2 inches long, and place on a lined baking sheet.

Whisk together 1 egg, a splash of water, 2 tablespoons of Kewpie mayonnaise, and 0.25 cup of plain flour in a bowl until smooth.

Dip each croquette in the batter, then roll in panko breadcrumbs until coated. Place back on the baking sheet.

Heat neutral oil in a deep frying pan to 350°F (180°C) and fry croquettes in batches for about 3–4 minutes per side until golden brown.

Serve warm with a dipping sauce like tonkatsu sauce or spicy mayo, and consider pairing with a green salad.