Place the all the marinade ingredients (except the green onion tops) in a bowl big enough to hold the pork, whisk to combine.
Add the pork, stir, cover and refrigerate for 1 hour.
Bring I quart water to a boil, add broccoli, cook for 1 minute to ‘blanch’, remove and rinse with cold water.
While broccoli is cooking, heat a large heavy skillet or wok over high heat for 3-4 min. Add sesame oil. When hot, add pork in 2-3 batches, browning and removing each batch to a plate. Add mushrooms, cook, stirring, 2-3 minutes, until cooked through.
Return pork (and juices) to pan, add broccoli, green onion tops, stir to blend. Cook for 1-2 minutes, until broccoli is warmed through.
Mix cornstarch with cool water. Push pork and broccoli to one side, add about 1/3 of the mixture, stir until sauce is thickened, stirring thoroughly to coat.
If there is extra liquid or the sauce seems thin, repeat with the last third of the mixture (this is not usually needed). Sprinkle with sesame seeds and serve with rice.
The Sauce - The need for a thickener (in this recipe, corn starch) varies depending on pan size, heat, ingredients used. You can adjust the amount of thickener needed and sometimes you may not need any. As a guide, we suggest approximately 1 teaspoon corn starch per 1/2 cup total liquid. Other Tools Chop sticks work very well for stirring the ingredients. A slotted spoon is handy for removing the ingredients as they are cooked.
Our Reviewers This is a very simple to make stir fry. The wonderful thing about these types of recipes is that you may substitute whatever vegetables you happen to have. Snow peas are excellent, mushrooms such as shiitake are a great addition. Boneless, skinless chicken breasts cut up into bite size pieces makes a good substitute for the pork. It is best to find fresh ginger. The flavor is pungent and depending on how much you use, it gives a nice "bite" to the stir-fry.
For The New Cook What is Stir-Fry? Stir-fry is simply a method of cooking small amounts of ingredients over very high heat while stirring. This method sears small bits of meat so that it is caramelized outside and juicy inside and vegetables are crisp and flavorful and retain most of their natural color.
Wok or No Wok? The problem with using a Wok in your home kitchen is that the average cook top does not produce enough heat to get the wok hot enough. You are more likely to steam or overcook the food. Unless you have a commercial quality cook top, we suggest using a heavy skillet.