Slice the steak against the grain into bite-sized pieces.
Combine the soy sauce, water, sugar, garlic and sesame oil in a medium bowl. Add the meat, and ensure the meat is well covered on all sides. Marinate for at least 30 minutes and up to 6 hours.
Make a cornstarch slurry by whisking the cornstarch and water together. Set aside.
In an oven-safe skillet large enough to hold all of the ingredients, heat the oil over high heat. Remove the steak from the bowl, reserving the marinade. Add the steak, and cook until just seared on all sides, about 1 minute per side.
Add the reserved marinade to the skillet, and bring to a boil. Reduce the heat to low, add the cornstarch slurry, and whisk to combine. Cook until syrupy, about 2-3 minutes, then add the rice, and toss well to coat. Add the vegetables, and toss to combine.
Bake for 15 minutes, then remove the casserole, and scatter with the steak pieces. Broil an additional 5 minutes, just to crisp up the steak.
Garnish with scallions and sesame seeds just before serving.
ADVERTISEMENT
