Heat oil in a large frying pan. Chop up onions and cook about 5-10 minutes on medium heat.

Chop up bell pepper, mushrooms, water chestnuts, and ginger if necessary. Add to pan and cook another 5 minutes or so with the onion until veggies are fragrant.

Put the vegetable mixture aside for now on plate or bowl so you can use the frying pan to cook the beef next.

Put ground beef, salt, pepper, and garlic powder in the pan. Use a spatula to move the meat around and cook evenly.

When meat is almost done (some fluid at the bottom of the pan and a little bit of pink meat too) add the cooked vegetables back to the pan along with the soy sauce.

Stir and cook another 5 minutes or so until the liquid has evaporated off and all of the meat is brown no longer pink. Set the pan aside to cool.

Take leaves off the head of lettuce individually and fill them with about 1/2 cup of the beef mixture.

Wrap up the lettuce like a burrito (or however you can manage) and enjoy!