Begin by slicing the boneless, skinless chicken breasts in half lengthwise to create thinner cutlets. In a shallow bowl, combine all-purpose flour with garlic powder, salt, and black pepper for seasoning. Beat two eggs in a separate bowl, and place panko breadcrumbs in a third bowl, ready for the breading process.

Dredge each chicken cutlet in the seasoned flour, shaking off any excess. Dip it into the beaten eggs, allowing the excess to drip off, then press the cutlet into the panko breadcrumbs to ensure the crumbs stick.

Heat about half an inch of vegetable or canola oil in a large skillet over medium-high heat until shimmering (approximately 350°F/175°C). Fry the breaded chicken cutlets for about 4-5 minutes on each side, or until golden brown and crispy.

In a medium saucepan, combine soy sauce, rice vinegar, sugar, honey, gochujang, minced garlic, and grated ginger. Simmer the mixture over medium heat, stirring occasionally, until it thickens slightly (about 3-4 minutes).

Transfer the cooked chicken to a plate lined with paper towels to drain excess oil. Drizzle the prepared sauce over the chicken katsu and garnish with sesame seeds or chopped green onions before serving.