Beef and Broccoli

INGREDIENTS:
 1 pound flank steak, cut into 1/4-inch-thick bite-sized pieces 1 tablespoon soy sauce 1 tablespoon rice wine vinegar 3-4 cups chopped broccoli florets (about 1 medium head of broccoli) 1 batch of sauce (see below) 1 tablespoon peanut oil 2 cloves garlic, peeled and minced optional garnishes: toasted sesame seeds and/or thinly-sliced green onions

Sauce Ingredients:
 3/4 cup water 3 tablespoons oyster sauce 3 tablespoons soy sauce 1 tablespoon cornstarch 1 tablespoon rice wine vinegar 1 teaspoon sesame oil 1/4 teaspoon ground ginger 1/4 teaspoon freshly-ground black pepper optional: 1-3 teaspoons sriracha

DIRECTIONS:
 TO MAKE THE BEEF AND BROCCOLI:
 Add the steak to a large bowl, along with the soy sauce and rice wine vinegar. Stir to combine, then let the steak marinate for at least 10 minutes (or up to 1 hour). Meanwhile, fill a large stockpot halfway full of water, and bring it to a boil. Stir the broccoli florets into the water, and cook for 30-45 seconds. Drain (or transfer the broccoli to a strainer), and set aside. Prepare the sauce (see instructions below). Once the steak has finished marinating, add the peanut oil to a large saute pan or wok over medium-high heat. Add the steak and garlic, and saute -- stirring occasionally -- until the steak is cooked through, about 5-6 minutes. Add the sauce and broccoli, and toss to combine. Continue cooking for 1-2 more minutes, or until the sauce comes to a simmer and thickens. Remove from heat and serve immediately, topped with optional garnishes if desired.

TO MAKE THE SAUCE: Whisk all ingredients together until combined.