Beef in Black Bean Sauce

Ingredients

3/4 pound steak, thinly sliced across the grain (leaving the meat in the freezer for half an hour makes slicing easier)

Marinade:

1/2 teaspoon sugar
2 teaspoons soy sauce
2 teaspoons Chinese rice wine or dry sherry
1 1/2 teaspoons cornstarch
1 tablespoon vegetable oil, such as canola
Other:
2 bell peppers, 1 green and 1 orange or red
1 small onion
400g tin black beans (the only supermarket I’ve found that regularly sells tins of black beans rather than black bean sauce is Morrisons)
2 cloves garlic
An inch of ginger (crushed)
4 tablespoons oil for stir-frying, or as needed (I usually use coconut oil)
1/2 cup stock

Method

Add the marinade ingredients to the beef and marinate for half an hour.
Remove the stems and seeds from the bell peppers and chop. Peel the onion and chop.
Chop the beans into small pieces and combine with finely chopped garlic and ginger.
Heat the wok to medium-high heat and 2 tablespoons oil. When the oil is hot, add the beef and briefly brown. Stir-fry until around 80% cooked. Remove the beef.
Add 2 tablespoons oil. When the oil is hot, add the bean mixture. Stir-fry briefly until aromatic and add the onion. Stir-fry for about 3 minutes, add the pepper.
Add the stock and bring to the boil.
Return the beef to the wok and reduce the heat to simmering for a few minutes.
Season with salt, pepper or soy sauce if desired. Serve hot.