Invented in a Calgary restaurant in the 1970s, ginger beef is crispy strips in a sticky sweet-spicy sauce. This version pan-fries lean beef with a light coating and less sugar.
Rinse the rice and cook it in 480 ml (2 cups) of water: bring to a boil over high heat, cover, simmer on low for 15 minutes and rest 5 minutes.
Slice the flank steak across the grain into thin strips about 5 mm (1/4 inch) wide. Toss with the egg whites, then with the cornstarch until every strip is coated.
Mix the soy sauce, rice vinegar, brown sugar, cayenne and 3 tbsp of water for the sauce.
Heat the oil in a wok or large skillet over high heat until it shimmers and just starts to smoke.
Fry the beef in three batches in a single layer for about 3 minutes per batch, turning, until crisp and browned. The thin strips reach 63°C (145°F) inside well within that time. Drain on paper towel.
Pour off all but 1 tsp of oil. Stir-fry the ginger, garlic, carrot and red pepper over high heat for 2 minutes.
Add the sauce and let it bubble for 1 minute until syrupy, then toss in the beef until coated.
Serve right away, while still crisp, over the rice with sliced green onion.