One of the most important feature of delicious tonkatsu is to have that crispy panko texture when you bite into it. Just like how I prepared Crispy Baked Chicken Katsu recipe. the key for panko to be crispy and golden brown is to pre-cook panko before breading the pork. That way you won’t need to spray or pour a lot of oil on panko in order for it to turn golden brown in the oven. Alto the pork loin could be overcooked and tough to chew while you wait for the panko to turn golden brown.