Place eggs in a medium saucepan and cover with cold water. Bring to a boil over medium heat. Once boiling, cover and remove from heat; let sit 10 minutes.

Transfer eggs to an ice water bath for 5–10 minutes. Gently peel the shells once cooled.

Slice eggs in half lengthwise and carefully remove yolks into a mixing bowl. Arrange the egg whites on a serving plate.

Mash yolks with a fork. Add mayonnaise, gochujang, rice vinegar, sesame oil, and garlic powder (if using). Mix until smooth and creamy. Taste and season with salt and pepper.

Spoon or pipe the yolk mixture into the egg white halves.

Sprinkle with sliced scallions, sesame seeds, and optional chili flakes.

Chill for 10–15 minutes before serving.