Slice the steak across the grain into 1/4-inch strips about 2 inches long.

Toss the beef with 1 tablespoon soy sauce, 1 tablespoon cornstarch, and 1 tablespoon water. Rest 15 minutes at room temperature, until each slice looks lightly coated.

While the beef rests, cut the broccoli into florets, mince the garlic, and grate the ginger. Whisk the broth, 2 tablespoons soy sauce, oyster sauce, brown sugar, 1 tablespoon cornstarch, and sesame oil in a small bowl.

Heat the skillet over medium-high heat for 2 minutes, until a drop of water skips across the surface. Add 1 tablespoon avocado oil and swirl until it shimmers.

Add half the beef in a single layer. Sear 1 to 1 1/2 minutes without moving, flip, and cook 1 minute more, until both sides are browned. Move to a plate.

Repeat with 1 tablespoon oil and the remaining beef, until browned on both sides.

Add the last tablespoon of oil and the broccoli to the pan. Stir 1 minute, until the florets turn brighter green.

Pour in 1/4 cup water and cover. Steam 2 to 3 minutes, until a fork pierces the stems with slight resistance.

Uncover, push the broccoli to the edges, and add the garlic and ginger to the center. Stir 30 seconds, until fragrant.

Whisk the sauce again and pour it in. Bubble 1 to 2 minutes, stirring, until glossy and thick enough to coat the back of a spoon.

Return the beef and its juices to the pan and top with green onions and sesame seeds. Toss 1 minute, until every piece is coated and the thickest slice reads 145°F.