1Whisk sauce: In a small bowl, combine the teriyaki sauce, beef broth, brown sugar, cornstarch, ginger, and minced garlic until smooth.
2Sear beef: Heat half of the vegetable oil in a large skillet or wok over high heat; sear the beef slices for 2-3 minutes until browned but not fully cooked, then remove and set aside.
3Sauté hard veggies: Add the remaining oil to the same pan and stir-fry the carrots and onions for 3 minutes until they begin to soften.
4Add green veggies: Toss in the broccoli and zucchini, continuing to stir-fry for another 3-4 minutes until the vegetables are vibrant and tender-crisp.
5Simmer sauce: Pour the prepared teriyaki sauce mixture into the pan with the veggies and stir constantly as it comes to a simmer and thickens into a glossy glaze.
6Combine: Return the seared beef and any accumulated juices back to the pan, tossing everything together for 1-2 minutes until the meat is fully glazed and heated through.
7Garnish: Remove from heat and generously sprinkle with toasted sesame seeds and sliced green onions before serving.