Slice the steak into 1 cm wide strips and place it in a bowl. (If your steak is more than 1 cm thick, cut the strips in half again length-wise)

In a food processor, blitz the onion, garlic, and ginger until it is a paste. (If you do not have a food processor, you can grate them or chop it very finely by hand, just make sure the ginger bits are very tiny)

Add the marinade and 1 tablespoon of soy sauce to the beef and mix well and marinate it in the fridge for 1 hour (or 20-30 minutes at room temperature)

After the beef has marinated, dust ½ cup of potato starch (or corn starch) on the beef and use your fingers to loosely coat the beef with it. Let it sit for 10 minutes

While you are waiting for the meat to marinate, heat up a heavy bottom pot (or wok) and set the stove to medium heat. Add at least 1 inch of oil to the pot and wait for it to get hot. (It should reach a temperature of 375F). I like to poke a wooden chopstick, or the handle of a wooden spoon into the oil and wait for it to bubble. Once it bubbles, the oil is hot enough.

Once the beef has marinated for 10 minutes, dust the other ½ cup of potato starch (or corn starch) on the beef again to lightly re-coat the beef and lightly dust off any excess starch. Deep fry it immediately.

Using your fingers separate the beef if they are clumped together and deep fry it in the oil in small batches (make sure the oil is hot but not smoking - to test if the oil is hot enough, add 1 small piece of beef first and see if it instantly sizzles)

Deep fry the beef for 1-2 minutes, and remove it from the pot onto a plate with parchment paper or newspaper.

Once all the beef has been cooked once (first fry), add all of it back in for the second deep fry for 1 more minute.

Remove all the oil from the pot and set it back on the stove on medium low heat

Add in all the sauce ingredients, except the corn starch slurry ingredients.

Stir until everything is combined well and wait until it comes to a low rolling boil

In a small bowl, combine the corn starch and cold water to make a corn starch slurry and add it into the sauce and keep stirring until the sauce has thickened. Turn off the heat.

Add in the crispy beef and coat it with the sauce

Serve immediately! Goes amazing with plain rice. :)