Start by cutting the peppers in half, remove all the core. After that, set aside.
Cut the onion into small dices.
Into a bowl, add the ground beef, the diced onion, the boiled rice, the canned corn, the ketchup, the soy sauce, the black pepper and the minced garlic cloves, mix all the ingredients very well until combined.
Once you’ve done that, transfer all the pepper halves to a large baking sheet and season each of them with a pinch of salt, a pinch of black pepper and a drizzle of olive oil. Rub all these spices on them very well.
Now fill all the peppers with the beef filling we’ve prepared.
Take them to a preheated oven at 190°C (374°F) and bake for 40 minutes.
Finally, distribute the grated mozzarella cheese all over the peppers.
Take them back to the oven and leave them there until the cheese melts and browns.
Serve.