01 - In a bowl, combine the beef with 1 tablespoon soy sauce, 1 teaspoon cornstarch, and 1 teaspoon sesame oil. Allow to marinate while preparing other ingredients.
02 - Whisk together soy sauce, oyster sauce, rice vinegar, Sriracha, brown sugar, water, and 1 teaspoon cornstarch in a small bowl. Set aside.
03 - Heat 1 tablespoon vegetable oil in a wok or large skillet over high heat. Add beef in a single layer and stir-fry for 2 to 3 minutes until browned. Remove from pan and set aside.
04 - Add remaining 1 tablespoon vegetable oil to the pan. Stir-fry broccoli and red bell pepper for 2 to 3 minutes. Add garlic and ginger; stir-fry for 1 additional minute.
05 - Return beef to the pan, pour in the prepared stir fry sauce, and cook while stirring for 2 to 3 minutes until sauce thickens and vegetables are crisp-tender.
06 - Serve immediately over jasmine rice, garnished with sliced spring onions if desired.