Fill a small pot with water, enough to cover the eggs by 1 inch, and bring to a rolling boil over high heat.

Gently lower the 6 large eggs into the boiling water with a slotted spoon and cook for 6–7 minutes for a jammy yolk.

Prepare an ice bath while the eggs cook by filling a bowl with cold water and plenty of ice.

When the timer ends, transfer the eggs to the ice bath and chill for at least 3 minutes to stop cooking.

Peel the cooled eggs under running water, starting from the wider end where the air pocket is located.

In a medium bowl, whisk together soy sauce, brown sugar, sesame oil, water, minced garlic, gochugaru, and rice vinegar until the sugar dissolves completely.

Place the peeled eggs in a glass jar or airtight container in a single layer and pour the marinade over them, ensuring they are fully submerged.

Seal the container and refrigerate for at least 4 hours, ideally overnight, to allow the flavors to penetrate.

To serve, halve or quarter the eggs, sprinkle with toasted sesame seeds and sliced scallions, and spoon extra marinade over the top.