Place a wok or wide frying pan over high heat until
hot. Add oil, swirling to coat sides. Add ginger
slices and cook, stirring, until fragrant, about 5
seconds. Add beef and stir-fry for 2 minutes or until
barely pink. Add sauce and stir-fry for 30 seconds.
Add cornstarch solution and cook, stirring, until
sauce boils and thickens. Garnish with orange slices.
[Personal note: this would probably be quite pretty
with thin orange peel curls, rather than, or in
addition to, orange slices.]
