Honey Garlic Beef

1 lb flank steak
1 tablespoon sesame oil
1/4 cup soy sauce
1 tablespoon Worcestershire sauce
1 teaspoon freshly grated ginger
1 teaspoon hot Chinese mustard
1/4 teaspoon red pepper flakes
1 teaspoon garlic minced
1/4 cup honey

Slice the flank steak into 2-inch chunks or longer, thinner strips across the grain.
Whisk together soy sauce, Worcestershire sauce, grated ginger, hot Chinese mustard, red pepper flakes, minced garlic, and honey in a medium bowl. Whisk to combine, then set aside.
Add sesame oil to a medium cast iron pan over medium-high heat.
Once the oil starts to simmer, add the sliced flank steak in one layer. Let it brown nicely for 1-2 minutes without turning it; then, use tongs to turn the beef on the other side to brown for another 2-3 minutes.
Reduce the heat to low-medium and add the sauce to the pan. Stir to combine, then simmer on low heat for about 5 minutes until it reduces by about half and creates a sticky glaze.
Serve the beef over rice. Garnish with chopped green onions and sesame seeds.

Source: Sweet and Savory Meals