Boil the Eggs: In a medium saucepan, fill with water and bring it to a rolling boil over high heat. Once boiling, gently lower in the medium eggs using a slotted spoon. Allow them to simmer for 6 minutes for perfectly jammy yolks.

Prepare Ice Bath: While the eggs are simmering, fill a large bowl with ice and cold water. Once the timer goes off, use a slotted spoon to transfer the hot eggs into the ice bath carefully. Allow them to sit for about 5 minutes.

Peel the Eggs: After chilling, gently tap the cooled eggs against a hard surface to crack the shells. Under running water, begin peeling each egg carefully.

Make the Marinade: In a mixing bowl, whisk together the soy sauce, minced garlic, brown sugar, sliced chili peppers, and sesame oil until the brown sugar has completely dissolved.

Marinate the Eggs: In an airtight container, arrange the peeled eggs in a single layer. Pour the marinade over the eggs, making sure each one is fully submerged.

Chill: Refrigerate the container of marinated eggs for at least 6 hours, though overnight is recommended for maximum flavor infusion.