• Cut 300 g potato(s) roughly into chunks (make sure they're about the same size) and add them to a pot of cold water. Add ½ tbsp salt and bring the water up to the boil, lower the heat to medium and cook until soft. (Pierce with a fork to test the doneness)
  
• While the potatoes are boiling, take a frying pan and heat it on medium. Add 15 g unsalted butter. Once melted, add 100 g yellow onion(s) and cook until softened and slightly translucent. (Don't let them brown.)
  
• Add 80 g ground beef and fry until it's cooked through.
  
• Next, add 1 pinch salt and pepper and 1 pinch nutmeg powder.
  
• Mix well and then add 1 ½ tbsp soy sauce, 1 tsp sugar and 2 tsp mirin.
  
• Fry until the liquid is absorbed, then turn off the heat and set aside to cool slightly.
  
• Transfer your cooked potatoes to a large heatproof bowl and mash them with 1 tbsp whole milk .
  
• Once the potato is smooth, add the mince and mix until the ingredients are evenly distributed.
  
• Transfer the mixture to a wide, heatproof container and leave to cool. Once cool to the touch, place a lid or plastic wrap over the top and chill in the refrigerator for 30 minutes.
  

Coating and frying

• Preheat your oil to 180 °C (356 °F). While waiting for it to heat up, make a batter by mixing 50 ml cold water, 1 medium egg(s) and 5 tbsp all-purpose flour together in a bowl.
  
• Prepare two plates, one with flour and one with 75 g panko breadcrumbs.
  
• Remove the filling from the fridge and divide into 4-6 pieces.
  
• Roll each piece into a flat oval shape.
  
• Coat the shaped korokke in plain flour, then the egg batter, then a generous coating of panko breadcrumbs.
  
• Place the korokke straight into the heated oil. I recommend cooking them in batches to avoid overcrowding the pan. (You can keep the other shaped korokke in the fridge/freezer while you wait for them to cook.)
  
• Once crispy and golden, transfer to a wire rack and rest for a few minutes to drain any excess oil.
  
• Serve with a drizzle of Worcestershire sauce and enjoy!