Heat 1 tablespoon of vegetable oil in a large skillet or wok over medium-high heat.
Add the ground beef and cook, breaking it apart with a spatula, until browned and cooked through, about 5-6 minutes. Drain excess fat if necessary.
Add the diced onion and minced garlic to the skillet with the beef. Cook for 2-3 minutes until the onion becomes translucent and fragrant.
Stir in the diced carrots and cook for another 3 minutes until slightly tender.
Push the beef and vegetable mixture to one side of the skillet. Add the remaining 1 tablespoon of vegetable oil to the empty side.
Pour the beaten eggs into the empty side and scramble until just set, about 1-2 minutes.
Mix the scrambled eggs with the beef and vegetables.
Add the chilled cooked rice to the skillet. Stir well to combine all ingredients evenly.
In a small bowl, whisk together the gochujang, soy sauce, sesame oil, and black pepper.
Pour the sauce over the rice mixture and stir thoroughly to coat everything evenly.
Add the thawed peas and cook for another 2-3 minutes until heated through.
Remove from heat and stir in the sliced green onions.
Sprinkle toasted sesame seeds over the top before serving.