Set your oven to 375°F (190°C) and allow it to preheat thoroughly. Meanwhile, take a baking dish that can accommodate the bell pepper halves closely. Coat the dish lightly with olive oil to prevent the peppers from sticking and to promote even cooking throughout the process.

Arrange the halved bell peppers in a baking dish with the cut side facing up. Lightly drizzle them with olive oil and sprinkle with salt. Roast in the oven at 375°F for about 10 minutes, until they begin to soften and edges start to brown slightly.

Heat a large skillet over medium heat and pour in 1 tablespoon of olive oil. Once the oil is shimmering, add diced onions. Stir occasionally and cook for about 5 minutes until they become translucent and release a sweet aroma, indicating they are ready.

Heat the skillet over medium heat and add the minced garlic, stirring continuously for about 1 minute until its aroma is released. Ensure the garlic does not brown, as this will cause it to taste bitter. Adjust the heat if necessary to prevent burning, maintaining a gentle sizzle.

Place the ground beef into the preheated skillet, using a spatula to break it into smaller pieces. Cook over medium heat for approximately 7 minutes, stirring occasionally. Continue cooking until the beef is evenly browned and no pink remains, ensuring it is fully cooked and safe to eat.

Add the cooked rice, tomato sauce, dried oregano, salt, and black pepper to the pan. Stir thoroughly until everything is evenly mixed. Ensure the mixture is moist, with a cohesive texture, but avoid making it too liquid. The aroma should be fragrant, indicating the spices are well incorporated.

Take the skillet off the heat source and allow the filling to cool for about 10 minutes. This cooling period is essential as it prevents burns and makes the mixture more manageable for stuffing into the bell peppers without spilling or causing any mess.

Carefully fill each bell pepper half with the prepared ground beef mixture, ensuring it is evenly distributed. Gently press the filling down to compact it, but leave a small gap at the top. This space will accommodate the shredded cheese later, preventing overflow during baking.

Sprinkle shredded cheese generously over each stuffed pepper, ensuring even coverage. Place the dish back into the preheated oven and bake for 15 minutes. Watch for the cheese to melt completely and develop a golden, bubbly surface, indicating it is ready to be served.

Once the stuffed bell peppers are baked to perfection, remove them from the oven and allow them to cool for about 5 minutes. This resting period helps the flavors settle. Just before serving, sprinkle with chopped parsley to enhance the presentation and add a fresh, vibrant touch to the dish.