Courtesy of Cook's Illustrated.

1.5 lbs flap meat (skirt steak or hangar steak can be used as substitutes)
3 tbsp soy sauce, divided
6 tbsp cornstarch
2 oranges
3 tbsp molasses
2 tbsp sherry
1 tbsp rice vinegar
1.5 tsp sesame oil
1 jalapeño, inner seeds and ribs removed, thinly sliced
3 garlic cloves, minced
2 tbsp freshly grated ginger
1 habañero, inner seeds and ribs removed, minced
2 scallions, thinly sliced
3 cups vegetable oil, for frying

Cut beef along grain into 3" lengths.
Then slice each piece against the grain into 1/2" strips.
If necessary, cut each slice lengthwise so that you end up with strips that are 3" x 1/2" x 1/2".

Toss the beef with 1 tbsp of soy sauce.
Next, sprinkle the beef evenly with the cornstarch and toss until coated.
Spread beef in a single layer on a wire rack set in a rimmed baking sheet.
Freeze until meet is very firm, but not completely frozen, about 45 minutes.

Use a vegetable peeler to peel off zest strips from both oranges. Do not use a bar zester - it peels off too much pith.
Then juice both oranges to yield 1/2 cup of juice.
Whisk the juice with the remaining 2 tbsp of soy sauce, molasses, sherry, vinegar, and sesame oil.

Line a baking sheet with a triple layer of paper towels.
Heat vegetable oil in a large Dutch oven over medium heat until oil registers 375 degrees F.
Carefully add 1/3 of the beef and fry, stirring occasionally to keep beef from sticking together, until golden brown, about 1 1/2 minutes.
Using spider or slotted spoon, transfer meat to paper towel-lined baking sheet.
Return oil to 375 and repeat twice with remaining beef.

Heat 2 tbsp of beef-frying oil in a large skillet over medium-high heat until shimmering.
Add orange peel and jalapeño and cook, stirring occasionally, until half of orange peel is golden brown, about 1 1/2 to 2 minutes.
Add the garlic, ginger, and habañero; cook, stirring frequently, until garlic is beginning to brown, about 45 seconds.
Add the soy sauce mixture and cook, scraping up any browned bits, until slightly thickened, about 1 to 2 minutes.
Add beef and scallions and toss to coat with sauce.
Transfer to platter and serve immediately.