Prepare the rice according to package guidelines; I prefer using Instant Pot brown or basmati rice.
As the rice cooks, heat a wok or large non-stick skillet over medium heat and add the ground beef, breaking it apart and stirring continuously for about 5-7 minutes until browned. Drain excess fat.
When the beef is nearly cooked, mix in the diced onion, minced ginger, and garlic, cooking together for 2-3 minutes with occasional stirring. Transfer the beef to a plate and set aside.
Add oil to the empty skillet, then toss in the diced bell pepper, sautéing for approximately 3 minutes while stirring occasionally.
Throw in the zucchini, eggplant, and tomato (if using), and continue sautéing for another 5 minutes, stirring from time to time.
Pour in the soy sauce, rice vinegar, maple syrup or honey, ground black pepper, and red pepper flakes. Stir well and cook for 1 more minute.
Return the cooked beef to the pan and combine everything thoroughly. Turn off the heat, sprinkle with chopped green onions, and stir once more.
Fluff the cooked rice with a fork and serve it topped with the flavorful Korean ground beef and vegetable mixture.
