Start by chopping the veggies. Peel the carrot and cut lengthwise into 1/2-inch thick slices. Stack the slices on top of each other and slice again into thin strips.
Cut off the top of the bell pepper and separate the pepper flesh from the white inner core. Discard the core and membranes then thinly slice into long strips.
Peel and grate the ginger and garlic; set aside.
Next cut the flank steaks against the grain into thin slices, about 1/4-inch thick.
Place the sliced beef and cornstarch into a large Ziploc bag. Shake well until fully coated with cornstarch.
Heat a skillet or a wok over medium-high heat. Add 1 tablespoon of oil. Add carrots, onions, and peppers, and sauté for 2-3 minutes until crispy yet tender.
Meanwhile, combine all the sauce ingredients in a bowl, whisk well, and set aside. Remove the veggies from the skillet and set aside.
Add the remaining 1 tablespoon of the oil to the skillet and heat until hot.
Add beef to the hot oil and sauté until it is seared on all sides but barely cooked in the center, about 2 minutes.
Once the beef is done, add in the sautéed veggies. Pour the prepared sauce and mix well until all the ingredients are well combined.
Cook for about 3 minutes until sauce thickens. Serve immediately and enjoy!