Heat the olive oil in a large skillet over medium heat and add in the diced onions. Cook for 3 minutes until they’re translucent.
Add in the shredded carrots and ground beef (or turkey) and cook until fully browned. Stir occasionally for even cooking.
Add black pepper, marinara sauce, and bay leaf to the skillet. Reduce heat to medium-low and let simmer for 10 minutes.
Prep bell peppers by cutting them in half lengthwise, seeding, and removing membranes from inside each pepper half.
Once the mixture is done simmering, stir in uncooked rice and let cook for a few minutes until done.
Preheat oven to 350 F degrees. Fill pepper halves with beef and rice mixture, then place on a baking sheet. Drizzle with olive oil and sprinkle with salt & cheese.
Bake in the oven for 30-35 minutes until peppers are softened and lightly browned. Serve.