In a small bowl, mix together the sauce ingredients: sesame oil, hoisin, rice wine vinegar, soy sauce, lime juice, salt, and black pepper. Set this aside for later.
5 tablespoons low-sodium soy sauce, 1 tablespoon sesame oil, 2 tablespoons rice vinegar, 2 tablespoons hoisin sauce, salt
Heat some cooking oil in a medium or large non-stick skillet over medium heat.
1 tablespoon vegetable oil
Sauté the mushrooms in the skillet over medium-high heat until they start to soften, about 2-3 minutes. Then, set them aside.
8-10 mushrooms
In the same skillet, add a little more oil and cook the ground chicken until it turns brown. When the chicken is halfway cooked, add the onions, red chili flakes, garlic, and ginger.
1 pound ground chicken, ½ cup yellow onion, 2 large garlic cloves, 1 teaspoon fresh ginger, 1 pinch red chili pepper flakes
Add the mushrooms back into the skillet, then mix in the chopped water chestnuts and the sauce. Stir everything together and let it simmer for a minute or two.
8-10 mushrooms, 8 ounces whole water chestnuts
Prepare your lettuce leaves and fill each one with about 2 heaping tablespoons of the mixture. Squeeze lime juice on top.
1 head butter lettuce, 1 ½ teaspoons lime juice
Top with any garnishes you like, such as white sesame seeds, chia seeds, green onion, and black pepper, then serve immediately.
green onions, sesame seeds, peanuts