In a small bowl or liquid measuring cup, whisk together the soy sauce, hoisin sauce, rice vinegar, brown sugar, oyster sauce (if using), Sriracha or chili-garlic sauce, and black pepper. In a separate small bowl, stir the cornstarch with the water until smooth, then whisk this slurry into the sauce. Taste and adjust sweetness or heat if desired.
1/4 cup low-sodium soy sauce, 3 tablespoons hoisin sauce, 1 tablespoon rice vinegar, 1 tablespoon brown sugar, 1 tablespoon oyster sauce, 1-2 teaspoons Sriracha or chili-garlic sauce, 1/4 teaspoon ground black pepper, 2 teaspoons cornstarch, 2 tablespoons water
Separate the lettuce leaves, rinse gently, and dry thoroughly with a clean towel or salad spinner. Stack the leaves on a plate and chill in the refrigerator. Finely dice the onion, bell pepper, and drained water chestnuts, and thinly slice the green onions.
1 small yellow onion, 1 red bell pepper, 1 can water chestnuts, 2 green onions, 1-2 heads butter lettuce, Bibb, or Boston lettuce
Heat the neutral oil in a large skillet or wok over medium-high heat. Add the ground chicken, breaking it apart with a wooden spoon or spatula. Cook for 5–7 minutes, stirring occasionally, until no longer pink and starting to brown in spots. If there is a lot of liquid in the pan, spoon off some so the meat can brown and the sauce will coat well.
1 1/2 tablespoons neutral oil, 1 1/2 pounds ground chicken
Reduce the heat to medium. Add the diced onion and cook for 2–3 minutes, until starting to soften. Stir in the garlic and ginger and cook for 30–60 seconds, just until fragrant. Add the diced red bell pepper and cook another 2–3 minutes, until crisp-tender.
1 small yellow onion, 3 cloves garlic, 1 tablespoon fresh ginger, 1 red bell pepper
Stir in the chopped water chestnuts and half of the sliced green onions. Give the prepared sauce a quick whisk, then pour it over the chicken mixture. Stir well to coat everything evenly. Cook for 2–4 minutes, stirring frequently, until the sauce thickens slightly and clings to the chicken and vegetables. Drizzle in the sesame oil, stir, then remove the pan from the heat.
1 can water chestnuts, 2 green onions, 1 teaspoon sesame oil
Taste a spoonful of the filling and adjust as needed. Add more Sriracha for heat, a small splash of rice vinegar or a squeeze of lime for brightness, or a tiny splash of soy sauce for more saltiness. When it tastes balanced to you, it is ready to serve.
Arrange the chilled lettuce leaves on a serving platter. Spoon 2–3 tablespoons of the warm chicken filling into each leaf. Top with the remaining sliced green onions, a sprinkle of toasted sesame seeds, and a squeeze of lime if desired. Serve immediately while the filling is hot and the lettuce is crisp.
1-2 heads butter lettuce, Bibb, or Boston lettuce, extra sliced green onions, toasted sesame seeds, lime wedges