Step 1

Toss flank steak in cornstarch in a large ziplock bag to coat evenly. Heat oil in a large pan over high heat.

Step 2

Working in batches, add steak in a single layer and cook for about 1 minute on each side, just until the edges are beginning to brown. Then transfer to a plate and repeat with remaining meat.

Step 3

Add ginger and garlic to the pan and saute 30 seconds. Add soy sauce, brown sugar, and water. Bring to a boil. Return the meat to the pan and toss in the sauce to coat. Cook for 2-3 minutes until slightly thickened. If the sauce doesn't thicken enough from the cornstarch coating on the meat, you can add a slurry made from 1 tablespoon of cornstarch and 1 tablespoon of cold water and cook until thickened.

Step 4

Add green onions and cook a final 30 seconds.

Step 5

Toss with the chopped green onions and sprinkle with the red pepper flakes. Serve over rice.