Preheat oven to 400°F. Prepare a baking pan with oil, parchment paper, or baking mats.
Wash red bell peppers and slice down the long edge of the pepper, splitting the stem in half. Remove seeds and place on baking pan. Optional to coat in oil.
Bake for 15-20 minutes until edges of bell pepper are roasted.
Wash remaining vegetables. Before chopping vegetables, steam bok choy, carrot, soybean sprouts, and mushrooms for 4-6 minutes (depending on how soft you prefer your vegetables).
Once steamed, finely dice bok choy, carrot, soybean sprouts, and mushrooms. Then, finely chop up green onions.
In a small bowl, mix all gochujang sauce ingredients together.
In a large bowl, thoroughly mix cooked rice, vegetables, and 1-2 Tbsp gochujang sauce (be sure to save some sauce to drizzle at the end).
Fill bell pepper halves with mixture (be sure to pack it into all the open spots). Bake again for 5 minutes.
Remove from oven, drizzle more gochujang sauce, top with some fresh green onion, and serve!