Fill a large pot with enough water to fully submerge the eggs and add a splash of distilled white vinegar.

Heat the water over medium-high until it reaches a rolling boil.

Once boiling, lower the eggs carefully using a spoon. Cook for about 7-9 minutes depending on desired doneness.

Immediately transfer eggs to an ice bath to halt cooking.

Peel the eggs under running water or in a bowl of water.

In a mixing bowl, combine garlic, ginger, soy sauce, mirin, cooking sake, and coconut brown sugar dissolved in hot water. Whisk until blended.

Place peeled eggs in a covered container and pour marinade over them. Seal tightly.

Let marinate in the refrigerator for at least 4 hours or overnight.

Slice the marinated eggs in half just before serving and sprinkle with green onions and sesame seeds.