Prep everything first (mise en place): thinly slice the cabbage and onion, rinse and drain the bean sprouts, mince the garlic and ginger, mix the soy-oyster-rice vinegar-brown sugar into a bowl, and whisk the cornstarch into 2 tablespoons of cold water to make a slurry. Having ingredients ready prevents overcooking and keeps the stir-fry fast and bright.

Heat a large heavy-bottomed skillet or wok over medium-high heat until hot (about 2 minutes). Add 1 tablespoon of vegetable oil and swirl to coat. High heat is essential for a true stir-fry: it quickly caramelizes proteins and vegetables without steaming them.

Add the ground turkey in a single layer and let it sit, undisturbed, for 60–90 seconds to develop good contact with the pan — this creates Maillard browning and deeper flavor. Break the meat into bite-sized pieces with a spatula and continue cooking until mostly cooked through and caramelized in places, about 4–5 minutes total. Don’t crowd the pan; browning concentrates flavor.

Season the turkey with a pinch of kosher salt and half the black pepper, then push it to one side of the pan. Add the remaining 1 tablespoon vegetable oil to the empty side, then add the sliced onion. Sauté the onion for 1–2 minutes until it starts to soften and turn translucent — the separate oil pocket helps them cook quickly without cooling the pan and losing heat for the meat.

Add the minced garlic and ginger to the onion-oil area and cook 20–30 seconds until fragrant. Cooking aromatics briefly mellows raw sharpness and releases their oils — don’t let them burn or they’ll turn bitter.

Stir the turkey together with the onions/garlic, then add the sliced cabbage. Toss vigorously for 2–3 minutes: you want the cabbage to wilt slightly but remain tender-crisp so it keeps body and texture in the finished dish. Overcooking cabbage makes it limp and dulls the bright flavor.

Pour the prepared sauce (soy sauce, oyster sauce, rice vinegar, brown sugar) around the edge of the pan so it hits the hot surface and starts to reduce immediately. Toss everything to coat. Let the sauce bubble for 30–45 seconds to concentrate flavors before adding the cornstarch slurry — this ensures the slurry thickens a flavorful base rather than thin water.

Stir in the cornstarch slurry and toss for another 30–45 seconds until the sauce becomes glossy and clings to the meat and vegetables. Cornstarch briefly gelatinizes when heated and gives the stir-fry a silky, restaurant-style finish.

Add the bean sprouts last and fold them in for 20–30 seconds — just long enough to warm them through but not so long that they lose their snap. Finish with the sesame oil and remaining black pepper; sesame oil is aromatic and should be added at the end so its fragrance remains vibrant.

Taste and adjust seasoning: add a sprinkle of salt or a splash more soy if it needs salt, or a pinch of red pepper flakes for heat. Transfer to a warm serving platter and garnish with sliced green onions and toasted sesame seeds.

Serve immediately over steamed jasmine rice, cauliflower rice, or alongside soba/noodles. Stir-fries cool quickly; serving hot preserves the contrast of textures.