Slice and Marinate the Beef: Place steak in the freezer for 15-20 minutes to firm up. Slice thinly against the grain. In a medium bowl, combine the beef slices, 2 tbsp soy sauce, 1 tbsp cornstarch, and 1 tsp vegetable oil. Toss to coat and set aside.

Mix the Stir-Fry Sauce: In a small bowl, whisk together the beef broth, 3 tbsp soy sauce, brown sugar, and toasted sesame oil. In a separate tiny bowl, mix 1 tbsp of cornstarch with 2 tbsp of cold water to create the slurry. Keep separate.

Cook the Broccoli: Add 1/2 cup of water to a large wok or skillet and bring to a simmer. Add broccoli, cover, and steam for 2-3 minutes until crisp-tender and vibrant green. Remove broccoli and drain water from the pan.

Sear the Beef: Heat 2 tbsp of vegetable oil in the empty skillet over high heat. Add beef in a single layer and sear for 1-2 minutes per side until a brown crust forms. Cook in batches if necessary. Remove beef from the pan.

Bloom the Aromatics: Lower heat to medium, add garlic and ginger to the pan and sauté for 30 seconds until fragrant.

Create the Glossy Sauce: Pour the sauce mixture into the skillet. Bring to a simmer. Re-stir the cornstarch slurry and whisk it into the simmering sauce until it thickens and becomes glossy.

Combine and Serve: Return the seared beef and steamed broccoli to the pan. Toss to coat everything in the sauce. Serve immediately, garnished with sesame seeds.