Slice the steak against the grain as thin as you can get it but no more than 1/4″ thick bite-size slices.

Place the steak pieces in a Ziploc bag and add the cornstarch to coat the steak.

Seal the bag, shake and smoosh the meat all around in the bag to make sure the pieces are nice and coated.

Line a plate with a couple of paper towels.

To cook the beef: Heat the cup of oil in a frying pan until nice and hot, (a piece of the beef immediately starts to sizzle when you add it.) Carefully add the beef in batches to the oil and sauté for a total of 2-3 minutes until the beef just begins to darken on the edges, stirring and flipping as needed to help it cook evenly. After a couple of minutes use a large slotted spoon to take the meat out and place it on the plate lined with paper towels. Repeat with the rest of the meat in batches until it is all done. Set aside.

For the sauce: Heat the 2 Tbsp of canola oil in a large deep pan over med/low heat.

Add the ginger and garlic to the pan and cook for just 1 minute.

Add the soy sauce, water, brown sugar and (optional) red pepper flakes, bring to a boil then reduce heat to medium and let simmer for 5 minutes.

Stir in the cornstarch and water mixture, let continue to cook and just slightly thicken for 1 more minute. Add in the cooked beef and cook for 1-2 minutes stirring to make sure all the meat is covered in sauce.

Stir in the sliced green onions then remove immediately from the heat.

Serve over rice and garnish with more sliced green onions and sesame seeds if desired.