Method

• Preheat the oven to 375°F (191°C) for about 10 minutes, or until fully heated; steady oven heat promotes even moisture evaporation and consistent roasting.
• Arrange the pepper halves cut-side up in the 9 x 13-inch (23 x 33 cm) baking dish and roast at 375°F (191°C) for 15 minutes, until they begin to soften and small beads of moisture appear inside.
• While the peppers roast, heat the olive oil in the 12-inch (30 cm) skillet over medium heat for 30 seconds, add the onion, and cook for 4 to 5 minutes until translucent and lightly golden at the edges.
• Add the garlic and ground beef to the skillet over medium-high heat and cook for 6 to 8 minutes, breaking the beef into small pieces, until no pink remains, browned spots develop, and the meat reaches 160°F (71°C).
• Reduce the heat to medium-low, add the salt, black pepper, Italian seasoning, cooked rice, and tomato sauce, and cook for 2 to 3 minutes, stirring until evenly combined and steaming with no loose liquid pooling in the skillet.
• Remove the peppers from the oven after their 15-minute roast, divide the filling evenly among the 12 halves, and sprinkle 1 cup (113 g) of the mozzarella over the filling; work while everything is hot so the filling continues heating evenly.
• Pour the water around, not over, the peppers, cover the baking dish with foil, and roast at 375°F (191°C) for 15 minutes, until the pepper walls are easily pierced with a knife and the filling is hot throughout.
• Remove the foil, sprinkle the remaining ½ cup (57 g) mozzarella over the peppers, and roast uncovered at 375°F (191°C) for 7 to 10 minutes, until the cheese is fully melted with light golden spots and the filling reaches at least 165°F (74°C).