Tofu with Crab Meat

Ingredients:
8 oz. crabmeat, with the shell and cartilage removed, flaked
3 tbsps. peanut oil
2 scallions, chopped
3 cakes fresh tofu
1 2-inch fresh ginger root, peeled and chopped
1 1/2 tsp. salt
3 tbsp. chicken stock
½ tsp cornstarch mixed with 5 tsp cold water
5 watercress sprigs
Cooking methods:
Slice each tofu into 1/4-inch slices, then cut each slice in half.
Heat the wok over high heat for 30 seconds. Add the oil.
When the oil is ready, reduce the heat to moderately high. Add scallions and ginger and stir fry for 1 minute.
Add tofu, salt and stock, bring to boil. Cover and cook for 3 minutes.
Stir in the crabmeat and cook for 1 minute.
Stir in cornstarch and cook, stirring constantly, until the liquid thickened.
Garnish with watercress and serve immediately.