Combine the cornstarch, soy sauce, freshly ground black pepper, and beef in a medium-size bowl and stir to coat the meat. Allow to marinate at room temperature for 15 minutes.
1 pound beef tenderloin, flank steak, or sirloin steak, 2 teaspoons cornstarch, 1 teaspoon soy sauce, Pinch of freshly ground black pepper
Put all the brown sauce ingredients into a small jar with a tight seal. Shut the lid tightly and shake to combine. Set aside.
1/2 cup chicken stock, 1 Tablespoon oyster sauce, 1/2 Tablespoon soy sauce, 1 teaspoon cornstarch, 1/2 teaspoon brown sugar, 1/4 teaspoon sesame oil
Add the peanut oil to a large skillet or wok and heat over medium-high heat. When the oil is hot, add the beef and stir-fry 3-5 minutes, just until the meat is no longer pink. Remove the meat from the pan and set aside.
1 1/2 Tablespoons peanut oil
Add the garlic and stir-fry just for a few seconds, then add in the broccoli and water. Stir-fry until the water has evaporated and the broccoli is tender-crisp.
3 garlic cloves, 4-5 cups broccoli florets, 1/4 cup water
Return the beef to the pan with the broccoli and add the brown sauce. Toss and stir another 2 minutes, until the sauce has thickened just a bit, then remove from the heat and transfer the prepared beef with broccoli to a serving dish. Garnish with sesame seeds, if desired, and serve with rice.
Sesame seeds