In a small bowl, whisk together the cornstarch, soy sauce, oyster sauce, mirin, red pepper flakes, and sesame oil until the cornstarch is fully dissolved and there are no lumps. This creates a smooth, lump-free sauce that will thicken beautifully when it hits the hot pan. While the sauce rests, mince the garlic and ginger, then chop the green onions, keeping the white and green parts separated—the white parts will go into the pan for cooking, and the green parts will be used as a fresh garnish at the end. Pat the thawed frozen vegetables dry with paper towels to remove excess moisture, which prevents the dish from becoming watery and soggy.

Heat a large skillet or wok over high heat until very hot, then add the ground turkey and cook, breaking it apart with a spoon or spatula, until it's browned and cooked through (about 4-5 minutes). The high heat creates flavorful browning that builds the foundation of the dish. Once the turkey is cooked, add the minced garlic, ginger, and white parts of the green onions to the pan and cook for 1 minute, stirring constantly, until fragrant. I always add the aromatics after the meat because they only need brief cooking to release their flavor without losing their brightness.

Add the dried thawed vegetables to the turkey mixture and stir-fry for 2-4 minutes until they're heated through and have absorbed some of the savory flavors from the turkey. The vegetables should remain slightly tender-crisp, not mushy. This quick cooking preserves their texture and color while they absorb the umami flavors from the pan.

While the vegetables cook, bring a pot of water to a rolling boil. Add both packets of udon noodles and cook for exactly 1 minute, then drain well in a colander. Toss the drained noodles with a light coating of oil to prevent them from sticking together. The 1-minute cook time keeps the noodles slightly firm and prevents them from becoming mushy when they finish cooking in the sauce.

Add the cooked udon noodles from Step 4 to the turkey and vegetable mixture in the skillet, then immediately pour in the sauce mixture from Step 1. Stir everything together gently but thoroughly to distribute the sauce evenly. Let the mixture sit undisturbed for 1-2 minutes so the sauce can thicken slightly and coat all the noodles, then stir again until the cornstarch has fully thickened the sauce to a glossy consistency. I like to watch the sauce carefully—once it becomes glossy and coats the back of a spoon, it's ready to serve, which usually takes just a minute or two of gentle stirring.

Remove the pan from the heat and divide the noodle mixture among serving bowls. Top each bowl with the reserved green parts of the green onions for a fresh, bright finish. Serve immediately while everything is hot and the sauce is still glossy.