A spicy-savory mix of Asian garlic chili, ketchup, sesame garlic, soy sauce, and Thai sweet chili really help to double down on the flavor profile of this Kung Pao Beef.
Slice flank steak thin against the grain. Place sliced beef in a large bowl and sprinkle cornstarch over the meat. Using gloved hands, combine cornstarch with the meat and set aside while you make the sauce.
In a medium bowl, combine all sauce ingredients and whisk together until combined well.
Cut green pepper and red Jalapeno peppers into strips, removing pith and seeds.
Add vegetable oil to wok and heat over medium-high until hot and shimmering.
Add green pepper and red Jalapeno pepper strips to the hot oil and stir fry for 2 minutes.
Add ginger and red pepper flakes, tossing with peppers, cooking for about 1 minute.
Add meat to the wok and stir fry for approximately 5-6 minutes until most pink is gone.
Pour sauce into the wok and stir to combine with meat and vegetables.
Add cilantro, green onion, and peanuts and stir to combine.
Reduce heat to medium and cook for an additional 3-4 minutes.
Notes
We chose to use red Jalapeno peppers instead of dried chilies. If using dried chili peppers, you can soak them in water for about 15 minutes before draining and adding them to the wok. We like using the jalapeños because they can be eaten rather than just being used for heat like dried chilies.
Store leftovers in an air-tight container kept in the refrigerator for 3-4 days. Reheat in the microwave, adding a dash of water to loosen it up if needed.