Cut each chicken breast in half lengthways, creating four fillets. Put each fillet between two sheets of baking parchment and beat with a rolling pin to even out the thickness.
Pour the milk into a bowl and season with a large pinch of salt, then add the chicken fillets. Cover and leave in the fridge for at least 20 mins or for up to 24 hrs (the longer you leave the chicken in the milk, the more succulent it will be).
When you’re ready to coat the chicken, tip the flour, eggs and breadcrumbs into three separate bowls, then season the flour with the togarashi and stir the soy sauce into the eggs. Scoop one chicken fillet out of the milk and coat in the flour mix, then dip into the egg mix and coat in the breadcrumbs. Set on a plate and repeat with the rest of the chicken fillets. Can be prepared up to a day ahead and frozen for up to a month.
To make the curry sauce, heat the butter in a saucepan and sizzle the carrot and onion for 5 mins, then add the garlic and ginger and cook for a few mins more. Scatter over the curry powder and cook for 1 min, then stir in the honey, ketchup, miso paste and soy sauce to create a sticky paste. Cook for 1 min more, then pour in 700ml boiling water and crumble in the stock cube. Cover and simmer for 20 mins until the carrot is soft. Tip the sauce into a blender and blitz until completely smooth (alternatively, use a hand blender). Season to taste. Can be made up to three days ahead and chilled or frozen for up to three months.
To cook the katsu, heat a good layer of oil in a large frying pan, then add as many of the chicken fillets as you can fit and fry for 3-4 mins on each side until deep golden and crisp. Transfer to a tray and keep warm in a low oven while you cook the remaining fillets.
Mix the cabbage and seaweed and sprinkle over some sesame seeds, if using. Top the katsu with the curry sauce and serve with the rice and salad, if you like.