Roughly chop and saute the onion. Puree in blender with dry chiles and water. Add black bean sauce, sweet chili sauce, and tomato paste and puree. Adjust flavor with sugar. Add water, as needed, to reach desired consistency.
Fill wok with enough oil to fry or poach the beef. Slice the beef into strips and coat lightly with potato starch. Carefully fry in hot oil for 2 minutes.
Add enough sauce to coat meat. Just before plating add scallions, cilantro, and peanuts. Garnish with steamed choi sum.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.