Partially freeze the beef: Place the trimmed beef in the freezer for 45–60 minutes. Slightly firm meat is easier to slice thinly and evenly.

Make the marinade: In a large bowl, whisk 1/2 cup low-sodium soy sauce, 3 tablespoons brown sugar, 1 tablespoon gochujang, 1–2 teaspoons gochugaru (optional), 1 tablespoon rice vinegar, 1 teaspoon toasted sesame oil, 2 tablespoons honey, 3 minced garlic cloves, 1 tablespoon grated ginger, 1 teaspoon black pepper, and 1/2 teaspoon onion powder (optional).

Slice the beef: Using a sharp knife, slice the beef against the grain into 1/8- to 1/4-inch thick strips. Thinner strips yield drier, crisper jerky; thicker strips stay chewier.

Marinate: Add the beef to the marinade and toss to coat. Cover and refrigerate for at least 6 hours, preferably overnight (12–18 hours for maximum flavor). Stir once or twice to ensure even soaking.

Drain and pat dry: Remove the beef from the marinade and pat each strip dry with paper towels. This step helps the jerky dehydrate instead of steam.

Prep the air fryer: Lightly oil or spray the basket or racks. Preheat to 180–200°F (82–93°C) if your air fryer allows. If not, set it to the lowest possible temperature.

Arrange the strips: Lay the beef in a single layer with space between pieces. Avoid overlapping. If you have a rack-style air fryer, use multiple racks.

Cook low and slow: Air fry at 180–200°F for 2 to 3 hours, flipping and rotating racks every 30–45 minutes. Check early and often—different models vary. If your air fryer’s minimum temp is higher (like 250°F), reduce time and monitor closely.

Test for doneness: Jerky should be dry to the touch, darker in color, and bend without snapping. When bent, it should crack slightly on the surface but not break cleanly.

Optional finish: For a glossy, lightly sticky finish, brush very thinly with honey diluted with a splash of water during the last 10 minutes. Sprinkle sesame seeds if you like.

Cool and condition: Let jerky cool completely on a rack. Place cooled jerky in a clean, loosely covered container or paper bag for 12–24 hours to equalize moisture. This prevents some pieces from being too dry or too soft.

Garnish and serve: Toss with a few sesame seeds and sliced green onions just before eating if you want a fresh pop of flavor.