Start by placing the boneless skinless chicken thighs between two sheets of plastic wrap. Using a meat mallet, pound the chicken to an even ½-inch thickness.

In a shallow dish, combine the large eggs, all-purpose flour, salt, and ground black pepper. Whisk until you achieve a slightly loose batter.

Dredge each pounded chicken piece in the egg batter, then dip it into the panko breadcrumbs.

Heat neutral oil in a large skillet over medium-high heat until it reaches 350°F. Add the coated chicken and fry for 4-6 minutes per side.

To assemble, moisten a Spam can or musubi mold. Place a sheet of nori, fill with ½ cup sushi rice, drizzle tonkatsu sauce, and top with crispy chicken.

Wrap the nori around the musubi, sealing it with a little water. Allow to sit for a minute, then slice for serving.