Add all sauce ingredients into a medium sized bowl and whisk together. Set aside.

In a large skillet over medium-high heat, add avocado oil.

When oil is warm, add chopped pepper and onion and sauté for 3-4 minutes until starting to sear.

Add beef and brown, breaking it up with a spatula into small pieces as it cooks.

Once beef is browned, add about half of the sauce and stir in, letting the beef cook another 2 minutes while you continue to break into small pieces.

Add carrot, water chestnuts, and remaining sauce. Let cook 2-3 minutes longer, stirring to mix sauce evenly in.

Remove from heat, add cilantro, green onion, and stir lightly. Sprinkle with sesame seeds and serve with lettuce.