Preheat your oven to 375°F (190°C).
In a medium saucepan, combine 1 cup of jasmine rice, 2 cups of water, and a pinch of salt. Bring it to a boil over medium-high heat. Once boiling, reduce the heat to low, cover, and simmer for 18-20 minutes.
While the rice is cooking, prepare the beef bulgogi filling in a large skillet over medium heat, add the ground beef and cook for about 5-7 minutes until browned.
Add the minced garlic and ginger to the skillet with the beef, stirring constantly for about 1 minute until fragrant.
Stir in the soy sauce, brown sugar, sesame oil, Gochujang, and rice vinegar. Mix well and let it simmer for another 2-3 minutes.
Incorporate the sliced onions, mushrooms, carrots, scallions, and sesame seeds into the beef mixture. Cook for an additional 5 minutes until the vegetables are softened.
Prepare the bell peppers by cutting the tops off and removing the seeds. Drizzle olive oil inside each pepper and season with salt and pepper.
Once the rice is cooked, fluff it with a fork and mix it gently into the beef filling.
Stuff each bell pepper generously with the beef and rice mixture, packing it down gently. Place in a baking dish.
Cover the baking dish with aluminum foil and bake for 25-30 minutes. Remove the foil for the last 5 minutes if you want a slight char on top.