Cook the rice: Start the rice first so it's warm and ready when the beef finishes. White rice takes about 18 minutes to cook through and fluff up.
Dry and coat the beef: Pat the ground beef dry with paper towels to remove excess moisture. Toss it with the cornstarch in a bowl until every piece is lightly coated.
Heat the skillet: Heat the vegetable oil in a large skillet over medium-high heat until it shimmers. A wide pan keeps the beef from steaming in its own juices.
Brown undisturbed: Add the beef in one even layer and let it sit untouched for 3 minutes. The bottom should turn deep golden-brown with a steady sizzle, not a wet hiss.
Break up and crisp: Use a spatula to break the beef into crumbles. Cook 2 to 3 more minutes, stirring occasionally, until several pieces show crisp, caramelized edges.
Add aromatics: Push the beef to one side and add the garlic and ginger to the open space. Cook for 30 seconds until fragrant, then stir them through the beef.
Build the glaze: Pour in the soy sauce and brown sugar, stirring to combine. Let it bubble for about 2 minutes until it thickens and coats the beef in a glossy layer.
Finish with sesame oil: Stir in the sesame oil and red pepper flakes, if using, off the heat. This adds a toasted, nutty aroma without burning the oil.
Fry the eggs (optional): In a separate small pan, fry the eggs over medium heat until the whites are set and the edges turn lacy and golden, about 3 minutes.
Assemble the bowls: Divide the warm rice among four bowls and top with the glazed beef. Finish with sliced green onions, sesame seeds, and a fried egg on top if desired.
