Prepare rice according to the package instructions; I usually opt for Instant Pot brown or basmati rice.
Heat a large deep ceramic skillet or wok over medium heat and add the ground beef. Cook, breaking it into small pieces and stirring often, for about 5 to 7 minutes until browned, then drain excess fat.
Add diced onion, minced ginger, and garlic to the beef and cook together for another 2 to 3 minutes, stirring occasionally. Remove the beef mixture from the skillet and set aside.
Coat the skillet with oil and add the diced bell pepper, sautéing for 3 minutes with occasional stirring.
Mix in the diced zucchini, eggplant, and tomato (if using) and continue to sauté for 5 minutes, stirring every now and then.
Pour in the soy sauce, rice vinegar, maple syrup or honey, then season with black pepper and red pepper flakes. Stir and cook this sauce for 1 minute before returning the cooked beef to the skillet.
Turn off the heat, sprinkle chopped green onions over the mixture, and give everything a final stir.
Fluff the cooked rice with a fork, then serve the Korean ground beef and vegetable mixture over the rice for a delicious, fresh dinner.
