Heat the oil in a large pan over a medium-high heat. Add the onion and carrot and cook for about 5 minutes, until softened. Add the garlic and ginger and cook for 30 seconds, just until fragrant. Stir in the curry powder and turmeric and cook for 1 minute.
Pour in the stock and coconut milk, bring to the boil, then simmer until the sauce has reduced by about half.
Blitz the sauce with a stick blender until smooth, then stir in the soy sauce and honey. Keep warm while you cook the chicken.
Cut the chicken breasts into small bite-sized pieces. Put the flour, eggs and breadcrumbs into three shallow dishes.
Coat the chicken first in flour, then egg, then breadcrumbs, pressing lightly so they’re evenly coated.
Heat about a 5mm depth of oil in a large frying pan over a medium-high heat. Shallow-fry the chicken, turning regularly, until golden, crispy and cooked through. Cut into a larger piece to check if you’re unsure. Alternatively, cook in an air fryer in a single layer, sprayed with oil, until crisp and cooked through.
Lift the chicken onto a plate or wire rack lined with kitchen paper to drain. Serve hot with the katsu sauce, plus rice and a crunchy salad if you like.