Preheat oven to 375°F. Line a rimmed baking sheet with foil, spritz lightly with non-stick cooking spray or spray oil. Pour the panko crumbs into a pie plate or round cake pan.

Lay the cod filets out on the prepared pan and season both sides with salt and pepper. In a small bowl, mix the mayonnaise and sriracha together until smooth. Brush it over the tops only of the cod. Take each cod filet ,working one at a time, and turn it mayonnaise side down into the panko crumbs and press lightly to help the crust adhere. Return each piece to the pan, crumb side up.

When all of the pieces have been coated, heat the butter in a frying pan over medium heat until it is fully melted and frothy. Ease the cod filets crumb side down into the hot butter and fry for 2-3 minutes, or until golden brown and crunchy. Carefully return each piece of cod to the prepared pan, crunchy crumb crust side up. Bake for 10-20 minutes, depending on the thickness of the filet, or until opaque all the way through and easily flaked with a fork. If your filet is under 1/2-inch thick, it will likely be done closer to the 10 minute mark, if thicker, closer to the 20 minute mark. The internal temperature of cod should reach 145°F to be done. Remove the pan from the oven and let rest for 3-5 minutes before plating or transferring to a serving dish.

Garnish with additional sriracha, thinly sliced green onions and toasted sesame seeds. Serve with hot cooked rice, noodles, another cooked grain like quinoa, or zoodles. This is accompanied beautifully by cucumber scallion salad.