Combine all sauce ingredients a small sauce pan. Bring just a bubble over medium-high heat. Then reduce to medium low and let simmer.
In a medium mixing bowl, add bell pepper. onion, and sesame oil.
In a large mixing bowl, combine flour, cornstarch, salt and ginger. Add steak strips to bowl and toss to evenly coat.
Add enough oil to a frying pan to be about ½ inch deep and put over high heat. Once up to at least 375degF, start add coated pieces of steak (shake a little to separate). Do not over crowd the pan. Cook for 2-3 minutes on each side. Remove to a baking rack over paper towels on a baking sheet. Repeat till all steak is cooked.
In a separate frying pan over medium high heat. add pepper mixture. Saute for about 5 minutes.
On a large serving dish, add pepper mixture to bottom in a mostly single layer. Pile crispy steak on top. Then pour sauce over top. Sprinkle with sesame seeds, if desired. Serve with rice or noodles.
Keyword beef, chinese fakeaway, chinese food, crispy steak, marinated steak, mongolian beef, red bell peppers, steak, white onion