Jjapaguri

Sear steak cubes quickly so they brown outside while staying tender.

Boil the noodles until chewy, reserving a little starchy cooking water.

Cook onion with the jjajang base, seafood spice, sesame oil, and enough noodle water to make a glossy sauce.

Toss noodles in the sauce until evenly coated, then fold in the steak.

Garnish with scallions and sesame seeds and serve hot.