Prepare lettuce ‘cups’ by removing the core from a head of lettuce then peel leaves, one by one, from the head of lettuce. Rinse lettuce cups in cold water then spin or pat dry. Refrigerate until ready to serve.
Place large skillet over medium-high heat then add the ground chicken. Break chicken into small pieces and cook just until no pink remains—about 5 minutes. The chicken does not need to be cooked through—just give it a head start.
Add onions, garlic and ginger then cook an additional 3–4 minutes, until onion softens and becomes translucent. Add hoisin garlic sauce, soy sauce, red wine vinegar and red pepper flakes. Stir to combine then allow the liquid to come to a bubble. Reduce heat to medium-low and let chicken cook in the sauce until it thickens and becomes a bit darker—about 8–10 minutes.
Stir in sliced green onions and water chestnuts then cook just until they are heated and the green onion begins to soften. Remove from heat then stir in sesame oil. Transfer filling to a serving dish and serve with crispy cold lettuce cups filled to the brim with this yummy filling. Enjoy!
Notes
Prepare your lettuce by removing the core then submerging it in cold water for a few minutes before you jiggle the leaves loose to keep it from tearing.