In a bowl, combine sherry, water, dark soy sauce, if using, and cornstarch and stir well into a smooth paste. Add beef and stir to coat well. Set aside for 10 minutes.
In a small bowl, combine chicken stock, soy sauce, sugar and salt and stir well.
Heat a wok or a large deep skillet over high heat. Add oil and swirl to coat pan. Add garlic and ginger and toss well, until fragrant, about 15 seconds. Add beef mixture and spread into a single layer. Cook, undisturbed, until edges change color, about 1 minute. Toss well.
Add chicken stock mixture, baby corn and water chestnuts. Cook, tossing occasionally, until beef is cooked through, about 2 minutes more. Add peas and cook, tossing once, for 1 minute more. Transfer to a serving plate. Serve hot or warm.
TIP: To freshen the flavor of canned baby corn cobs, drain well, cover with cold water and drain again. Transfer leftover baby corn to a jar with water to cover. You can slice baby corn cobs crosswise into 3 or 4 chunks or into thin rounds, and add them to soups and salads just before serving.
Recipe by Moms & Munchkins at https://www.momsandmunchkins.ca/stir-fry-recipes/