Prep the lettuce and veggies: Separate lettuce leaves, rinse, and pat dry.
Dice the onion and bell pepper, mince garlic and ginger, and chop mushrooms if using. Keep everything within reach.
Make the sauce: In a small bowl, whisk together soy sauce, rice vinegar, hoisin (or honey), sesame oil, and sriracha. If you like a thicker glaze, stir in the cornstarch slurry.
Brown the turkey: Heat a large skillet over medium-high heat.
Add the oil, then the ground turkey. Break it up with a spatula and cook until no longer pink, about 5–6 minutes. Season lightly with a pinch of salt.
Add aromatics: Stir in onion, garlic, and ginger.
Cook 2–3 minutes until fragrant and the onion softens slightly.
Stir in vegetables: Add bell pepper, carrot, and mushrooms. Cook 3–4 minutes, stirring often, until tender but still crisp. You want a bit of bite for texture.
Sauce it up: Pour the sauce into the skillet.
Stir to coat the mixture evenly. Let it simmer 1–2 minutes until slightly thickened and glossy. Taste and adjust seasoning—more soy for salt, vinegar for brightness, or sriracha for heat.
Assemble: Spoon the turkey-veggie mixture into lettuce leaves.
Top with green onions, sesame seeds, and a squeeze of lime if you like.
Serve right away: These are best when the filling is warm and the lettuce is cold and crisp.