Combine soy sauce, sugar, sesame oil, cornstarch, and water in a small bowl, whisking until the cornstarch dissolves completely. This sauce will thicken and coat the bok choy at the end.
Trim the base of each bok choy head, then gently separate the leaves. Rinse them under cold water, paying attention to the base where dirt often hides.
Drop the bok choy into boiling water for exactly 20 seconds — just long enough to brighten the color and soften slightly. Immediately plunge into an ice bath to stop the cooking.
⏱ 20 sec
Drain the bok choy thoroughly, pressing gently to remove excess water. Too much moisture will make the final dish watery.
Combine minced garlic, gochujang, and peanut oil in your wok or large skillet, stirring to create a paste.
Set the pan over medium heat and let the mixture warm gradually — rushing this will burn the garlic.
Cook the gochujang mixture for 1-2 minutes until fragrant and the garlic just starts to sizzle. The gochujang should darken slightly but not smoke.
⏱ 2 min
Add the drained bok choy and toss constantly for 2-3 minutes, coating every leaf with the spicy mixture. The leaves should glisten with the gochujang.
⏱ 3 min
Give your cornstarch slurry a quick stir, then pour it over the bok choy. Toss everything together until the sauce thickens and clings to the leaves, adding 1-2 tablespoons water if needed for a light, glossy coating.
Transfer to a serving plate and scatter sesame seeds over the top. Serve immediately while the bok choy still has some bite.