Wash and drain baby bok choy thoroughly. Trim ½ inch off the end of the stalks. Smaller leaves can be left whole with their stems. Longer leaves can be cut into two with the leaves on one end and the stem on the other end. Then cut stem into 2 length wise. Stems and leaves should preferably be separated.
Heat a wok or large pan. When it is hot, add vegetable oil. Sauté ginger for about 1 minute. Stir in garlic for 30 seconds. Add the baby bok choy stems and fried tofu (if using). Fry for about 2 minutes.
Now, add the rest of the baby bok choy and soy sauce. Stir fry for 1 to 2 minutes. Baby bok choy leaves should be wilted but still crunchy.
Pour in cornstarch mixture. Stir to combine for another 1 to 2 minutes. Corn starch mixture will thicken. Turn off heat.
Drizzle sesame oil over vegetables.
Remove and serve immediately.