Prepare the Peppers:
Preheat your oven to 375°F (190°C). Cut the tops off the bell peppers and remove the seeds and membranes. Blanch the peppers in boiling water for 3-4 minutes to soften slightly. Drain and set aside.
Cook the Filling:
In a skillet, heat olive oil over medium heat. Add the onion and garlic, sautéing until fragrant. Add the ground meat, cooking until browned and crumbled. Stir in the diced tomatoes, tomato sauce, cooked rice, Italian seasoning, smoked paprika, salt, and pepper. Cook for 3-4 minutes to combine flavors.
Stuff the Peppers:
Arrange the blanched peppers in a baking dish. Spoon the filling mixture into each pepper, packing it firmly but not overflowing.
Top with Sauce:
Spoon a little extra tomato sauce over the tops of the stuffed peppers. If using cheese, sprinkle it on top.
Bake:
Cover the baking dish with aluminum foil and bake in the preheated oven for 25 minutes. Remove the foil and bake for an additional 10 minutes, or until the peppers are tender and the cheese is melted and bubbly.
Serve:
Let the stuffed peppers cool for a few minutes before serving.