This is my favorite recipe for broccoli beef. I like to eat it on a bed of cabbage or lettuce. The kids like with Chinese noodles.

3 tbsp soy sauce
1/4 cup beef broth
1 tbsp rice vinegar
1 tbsp sugar
3 cloves garlic , minced
1/4 tsp ground pepper
1 1/4 pounds flank steak, cut diagonally across the grain into 1/2-inch-by-3-inch strips
Canola oil
1 tbsp cornstarch
1 head broccoli, stems trimmed, peeled, and cut, florets separated into bite-size pieces
1 carrot, cut in thin strips
1/2 cup plus 3 tbsp water
Coarse salt

In a small bowl, mix soy sauce, broth, vinegar, sugar, garlic, and pepper. Place meat in a bowl or Ziploc bag; add marinade. Let sit for 10-15 minutes.

Heat 1 tablespoon oil in a nonstick skillet over high heat. Reserving marinade, cook meat in two batches until lightly browned, turning once, about 2-3 minutes per batch. Remove meat. Add 1/2 cup water to pan; stir up browned bits with a wooden spoon. Pour into marinade; whisk in cornstarch. Remove from pan.

In the same skillet, toss broccoli and carrots in 1 teaspoon oil over high heat until crisp. Add remaining 3 tablespoons water; cook until broccoli and carrots are tender but still have a bite, 6 to 8 minutes.
Stir in marinade, cook until thickened, 30 seconds. Return meat to pan; toss to coat. Season with salt and pepper.

Variations:
For a little kick add red pepper flakes or chopped red chili pepper.
Sometimes I like to sprinkle the dish with toasted sesame seeds.