Beef and Broccoli

Combine beef and soy sauce in a shallow pan, cover and refrigerate for 10 minutes to 1 hour.
While beef is marinating, in a small bowl, whisk together the rice vinegar, chicken broth, soy sauce, brown sugar, sesame oil and cornstarch, set aside. In another small bowl combine the garlic, ginger and 1 teaspoon vegetable oil, set aside.
In a large nonstick skillet, heat 2 teaspoons of oil over medium-high heat. And about half of the beef to the skillet in an even layer and cook for 1 minute before stirring, then stir and cook until beef is browned and barely cooked through. Transfer beef to a bowl and cover with foil. Heat another 2 teaspoons of oil in the skillet and cook the remaining beef like above and transfer to a bowl and cover with foil.
Add 1 tablespoon of oil to the skillet over medium-high heat and once hot, add broccoli and cook for 30-45 seconds. Add water and cover pan, cook broccoli about 2 minutes or until almost tender. Push broccoli out of the center of the pan and add the garlic, ginger and oil to the center of the skillet and cook, smashing with a spoon, for about 30 seconds until fragrant. Add the beef back to the skillet and stir to combine. Pour sauce over everything and cook until the sauce is thickened, about 2-5 minutes.
Serve over rice.