Preparation Steps:

• Start by slicing the sirloin beef tips thinly against the grain. In a bowl, combine the sliced beef with cornstarch, baking soda, and 1 tablespoon of low-sodium soy sauce. Toss to coat evenly and set aside to marinate for about 15 minutes.
• In a small bowl, whisk together the remaining low-sodium soy sauce, water, dark brown sugar, and flour until smooth. Set this sauce mixture aside.
• Heat a wok or large skillet over medium-high heat. Add 2 tablespoons of sesame oil and allow it to heat until shimmering.
• Add the marinated beef to the hot wok in a single layer. Sear the beef for about 2-3 minutes without stirring, then stir-fry until cooked through, about another 2-3 minutes. Remove the beef from the wok and set aside.
• In the same wok, add more oil if necessary, then toss in the minced garlic and grated ginger. Sauté for about 30 seconds until fragrant, then add the frozen stir-fry vegetable mix. Stir-fry for 5-7 minutes until the vegetables are tender but still crisp.
• Return the cooked beef to the wok and pour the prepared sauce over the mixture. Stir everything together until well coated and the sauce has thickened, about 2 minutes. Serve immediately over cooked rice, garnished with crushed red pepper flakes if desired.