Follow these simple steps to create your mouthwatering Asian-Inspired Beef Lettuce Cups:

1. Prepare the Lettuce: Carefully separate the lettuce leaves, wash them thoroughly under cold running water, and pat them dry gently with paper towels or use a salad spinner. Aim for whole, intact leaves that can act as cups. Arrange them on a platter and refrigerate until ready to serve to keep them crisp.
2. Mix the Sauce: In a small bowl, whisk together the low-sodium soy sauce, hoisin sauce, rice vinegar, brown sugar, and sriracha (if using). Set aside. In a separate tiny bowl, mix the cornstarch with 1 tablespoon of cold water to create a smooth slurry. Set this aside as well.
3. Sauté Aromatics: Heat the avocado oil in a large skillet or wok over medium-high heat. Once the oil is shimmering, add the chopped yellow onion and cook for 3-4 minutes, stirring occasionally, until softened and translucent.
4. Add Garlic and Ginger: Add the minced garlic and grated ginger to the skillet. Sauté for another 1-2 minutes until fragrant, stirring constantly to prevent burning. Be careful, as garlic and ginger can burn quickly.
5. Brown the Beef: Add the lean ground beef to the skillet. Break it apart with a spoon or spatula and cook, stirring frequently, until it’s fully browned and cooked through, about 7-10 minutes. There should be no pink remaining.
6. Drain Excess Fat: If you’re using beef that isn’t extra lean, there might be excess fat in the pan. Carefully tilt the skillet and spoon out any significant accumulation of grease. This will prevent the filling from being too oily.
7. Incorporate Vegetables: Add the chopped water chestnuts and shredded carrots to the skillet with the cooked beef. Stir well to combine and cook for another 2-3 minutes, just until the carrots are slightly tender-crisp.
8. Add the Sauce: Pour the prepared sauce mixture over the beef and vegetables. Stir everything together to ensure the beef is evenly coated. Bring the mixture to a gentle simmer.
9. Thicken the Sauce: Give the cornstarch slurry a quick stir and pour it into the simmering beef mixture. Continue to cook, stirring constantly, for 1-2 minutes, or until the sauce has thickened slightly and appears glossy. It should coat the back of a spoon.
10. Stir in Green Onions & Sesame Oil: Remove the skillet from the heat. Stir in the sliced green onions (reserving some for garnish) and the 1 tablespoon of sesame oil. The sesame oil is added off-heat to preserve its delicate, nutty aroma.
11. Taste and Adjust: Give the filling a taste. If needed, you can adjust seasonings – perhaps a little more soy sauce for saltiness, a touch more sriracha for heat, or a tiny bit more brown sugar for sweetness.
12. Serve: Spoon the warm, savory beef mixture into the prepared crisp lettuce cups. Garnish with extra green onions, toasted sesame seeds, chopped cilantro, or any other desired toppings. Serve immediately and enjoy the explosion of flavors!