Brown the beef. Heat a large skillet over medium-high heat. Add the ground beef and cook for 5–7 minutes, breaking it into small pieces as it cooks, until browned and cooked through. Drain any excess grease if needed.
Add the garlic. Stir in the garlic and cook for about 30 seconds, just until fragrant.
Add the sauce. Stir in the soy sauce, brown sugar, sesame oil, rice vinegar, and black pepper. Simmer for 2–3 minutes, stirring occasionally, until the sauce has reduced slightly and coats the beef. There shouldn't be much liquid left in the bottom of the skillet.
Assemble the bowls. Divide the cooked rice among four bowls and spoon the Korean beef over the top.
Add the toppings. Top with cucumbers, carrots, kimchi, green onions, sesame seeds, a fried egg, or any other toppings you like. Add sriracha or gochujang for some heat, if desired.
Serve immediately.
Notes
Ground beef: Lean ground beef works well because there's less excess grease to drain. Ground turkey or chicken can also be used.
Sauce: Simmer the sauce with the beef for 2–3 minutes, until it reduces slightly and coats the meat.
Make it spicy: Add gochujang, sriracha, or bibimbap sauce for extra heat.
Toppings: Try sliced cucumbers, shredded carrots, kimchi, green onions, sesame seeds, or a fried egg.
Meal prep: Store fresh toppings separately and add them after reheating the beef and rice.
Storage: Refrigerate leftover beef in an airtight container for up to 4 days.