Cut the steak into strips then into thin slivers
against the grain. Heat the oil and fry the steak,
salt, pepper, onion and garlic until lightly
browned.
Add the potatoes and stock, bring to the
boil, cover and simmer for 10 minutes.
Add the
celery leaves and simmer for about 4 minutes until
just tender.
Blend the corn-flour, soy sauce and
water to a paste, add to the pan and simmer,
stirring, until the sauce clears and thickens.