Korean Lotus Root and Beef Stir-fry

Soak the evenly cut lotus root in vinegar water for 10 minutes to limit browning, then rinse and drain it thoroughly. Cut the beef into bite-size pieces, toss it with 1 tablespoon of the soy sauce, and leave it for 5 minutes. Keep the 80 g onion slightly thick so it softens without losing its shape. Heat 1 tablespoon cooking oil over medium heat and spread the beef in a single layer. Cook for about 1 minute, moving on while roughly half of the red color remains rather than finishing the meat by itself. Add the lotus root and onion and keep tossing for about 3 minutes. When the lotus root edges look translucent and the onion becomes aromatic, lower the heat to medium-low. Add the remaining 1.5 tablespoons soy sauce, 1 tablespoon oligosaccharide syrup, and 1 teaspoon minced garlic. Stir-fry for about 2 minutes, until the seasoning forms a thin glossy coating instead of collecting on the pan. Taste one lotus root slice before stopping: the center should still be crisp and the outside should carry the sweet-salty sauce. Turn off the heat and mix in 1 teaspoon sesame oil. Thinly sliced beef suits this timing because it cooks alongside the lotus root without requiring a longer final stage.