Preheat the oven to 400 degrees F and lightly coat a large casserole dish or baking dish with cooking oil. As an alternative, you can line a baking sheet with parchment paper.

Slice the chicken breasts through the center to create four thinner cutlets from two boneless chicken breasts in order to get even thickness throughout the chicken filets. This is an important step, as it helps the chicken cook through evenly without becoming over-cooked and omits the need to tenderize the chicken with a meat tenderizer.

Crack the egg into a shallow bowl and whisk it until it is well-beaten. Transfer the breadcrumbs, flour, salt and pepper to a large plate and stir it around with a fork until everything is well-combined.

Dredge a chicken cutlet in the beaten egg mixture, then coat it liberally in the breadcrumb mixture, making sure to get both sides. Repeat for the rest of the chicken.

Transfer the breaded chicken cutlets to the prepared baking dish and bake for 12 to 15 minutes, or until the chicken reaches an internal temperature of 165 degrees F and the outside is nice and crispy.

While the chicken is baking, stir together the ingredients for the sauce in a small bowl until creamy and well-combined.

Serve the baked chicken katsu with your choice of sides along with the spicy honey sriracha mayo.