Do ahead: Eggs can be marinated 2 days ahead. Cover and chill.

Gently lower eggs into a large saucepan of boiling water. When water returns to a gentle boil, cook for 7 minutes. Using a slotted spoon, transfer to a bowl of ice water and let cool for 2 minutes (eggs may still be a little warm). Remove eggs from ice water and peel.

Meanwhile, bring garlic, chiles, soy sauce, mirin, vinegar, and 2 cups water to a boil in a medium saucepan. Reduce heat; simmer 5 minutes. Remove from heat and add eggs. Let sit for at least 1 hour.

To serve, drain eggs, quarter, and sprinkle with sesame seeds if desired.

The longer you let them sit, the more flavor they’ll pick up, but if you only have an hour, serve egg quarters with some of the pickling liquid drizzled over for extra flavor.