Cut the beef across the grain into thin slices (easier when partially frozen).

Marinate the beef in a mixture of soy sauce, oyster sauce (if using), cornstarch, sesame oil, and sugar.

Set aside.

Remove stems and strings from sugar snap peas, leaving pods intact.

Rinse and pat dry with paper towels.

In a hot skillet or wok, add 2 tablespoons of vegetable oil.

Stir in salt, sugar snap peas, water chestnuts or bamboo shoots, and mushrooms.

Cook, stirring constantly, until peas turn a vibrant dark green (about 2 minutes).

Remove to a bowl.

In the same skillet, add the remaining 2 tablespoons of vegetable oil.

Add the marinated beef mixture and stir constantly until the beef is almost done (about 5 minutes).

Return the sugar snap peas, water chestnuts, and mushrooms to the skillet.

Mix well until heated through.