Beijing Beef

1.

Slice the beef sirloin into thin strips, about a quarter-inch thick, which helps the meat cook faster and absorb flavors.

2.

In a medium-sized bowl, coat the beef strips with cornstarch, ensuring each piece is well-covered to get the desired crispiness.

3.

Heat vegetable oil in a large skillet over medium-high heat and stir-fry the beef for about 5 minutes until browned and crispy.

4.

In another medium bowl, mix soy sauce, sugar, vinegar, and chili flakes to create a tangy, slightly spicy sauce for the beef.

5.

Add sliced red bell pepper and onion to the skillet with the beef and continue to stir-fry for about 5 minutes, until veggies soften.

6.

Pour the sauce mixture over the sautéed beef and vegetables, stirring well to coat, then cook for another 3 minutes until thickened.