Peel the onions, carrots, garlic & ginger. Finely chop the onions & carrots and grate the garlic & ginger.
Place a large saucepan over a medium heat then pour in 2 tbsp of vegetable oil. Let it heat up for a minute or so then add in the onions & carrots, plus a pinch of salt.
Fry the veg for 4-5 minutes, until soft then add in the garlic & ginger & cook for another minute. Make sure to stir the veg regularly to prevent it from catching on the pan.
Stir in the curry powder & turmeric, cook out for 2 minutes (stirring constantly) then stir in the flour & cook out for another minute.
Next, gradually pour in the chicken stock, stirring constantly to prevent any lumps.
Once all the stock has been incorporated, add in the coconut milk, soy sauce, brown sugar & the bay leaf. Let the sauce come to a simmer then cook for 15-20 minutes, until the veg is fully cooked & the sauce has thickened.If the sauce starts to boil, reduce the heat slightly to bring it back down to a simmer. Next, stir in the honey & sriracha then take the sauce off the heat. Leave to cool slightly, remove the bay leaf then blitz in a jug blender until smooth. Taste the sauce, to check the seasoning then add more salt if necessary.
Pour the sauce back into a saucepan then set aside. This will need to be reheated on the stove whilst we fry the chicken.The katsu curry sauce can be made up to 3 days in advance & stored in the fridge. To reheat, cook over a medium-low heat in a saucepan.