Place the sliced beef into a bowl and add the cornstarch. Toss gently to thoroughly coat the beef pieces with the cornstarch. Set aside for about 10 minutes (while you make the sauce) to allow the cornstarch to absorb the beef juices and stick to the beef.

Heat 1 tablespoon of oil in a medium saucepan over medium heat.

Add the garlic and ginger and sauté, stirring, just until they release their fragrance, about 30 seconds. Don't overcook them.

Carefully add the soy sauce, water and brown sugar. Be EXTRA CAREFUL that the hot oil does not spatter on you.

Raise the heat to medium-high and continue stirring until the brown sugar has dissolved and the sauce boils and thickens slightly, about 4 - 5 minutes. Remove pan from heat and set aside.

In a deep-sided skillet, add enough vegetable oil to mostly cover and fry the beef. (How much will depend on the size of the skillet. Just eyeball it. It's not that crucial.)

Heat the oil to medium-high heat. Do not let it smoke.

When the oil is hot, take the beef pieces out of the bowl, shaking them slightly to remove excess cornstarch, and drop them into the hot oil, a few at a time.

Stir briefly and sauté the beef until the edges become crisp and start to brown, about 2 minutes. Don't overcook the pieces as they are going to be cooked more later.

Remove the beef from the oil with a large slotted spoon. Drain on paper towels to remove excess oil. Set aside.

Pour the oil out of the skillet and return the pan to medium heat.

Return the beef slices to the pan and pour in the sauce. Stir a bit to combine and add the green onions. Bring the mixture to a boil and cook until the onions have softened and turned bright green, about 2 minutes.

Remove to plate with a slotted spoon or tong.

Serve with rice.