If you are making your own panko crumbs. Simply pop two slices of toast into the toaster. Allow to cool fully. Then, add to a food blender with cornflakes and whizz till you have a nice crumb mix.
If you can’t find or don’t have black sesame seeds its okay to just sub with all white sesame seeds.
Mirin is a sweet Japanese cooking wine, to sub it I’ve used a combination of distilled white vinegar sugar. You could also sub dry sherry. Rice vinegar and sugar.
If using vinegar use 3 tbsp vinegar to 2 tbsp sugar.