Preheat the oven to 400°F. Prepare the bell peppers by neatly slicing off the tops and removing the ribs and seeds. Keep the tops, but discard the ribs and seeds. Arrange the hollowed-out peppers in a baking dish. The sides of the baking dish do not need to tower over the peppers, but should come up most of the way to avoid any spillage.
Start the Filling: Heat a skillet over medium high heat and add the olive oil. Saute the diced fennel for about a minute. Add the rosemary, and saute for another minute. Add the ground pork and chicken to the pan, season with salt and pepper, and stir to combine. Saute the meat until browned and no longer pink, about 10-12 minutes.
Stir the pre-cooked brown rice, one cup of the grated parmesan, and two cups of Creamy Tomato Sauce into the meat mixture. Remove the skillet from heat, and carefully stuff each hollowed out bell pepper until full. Top them with the remaining sauce, pouring any extra sauce and filling into the pan around the peppers. Set the tops back onto the peppers, and bake for 15-20 minutes. Cover the peppers with foil, and bake another 30 minutes.
Stir together the cans of tomato sauce and roasted diced tomatoes in a medium saucepan over medium-high heat. Let simmer for 5 minutes. Stir in the coconut milk (or heavy cream) until combined. Add most of the basil, and season with red pepper flakes, salt, and pepper. Let the sauce reduce over low heat while you work on the other components (15-20 minutes). The sauce can be made 1-2 days ahead and stored in the fridge until use.
Make-Ahead Dinner: Once made, stuffed peppers can be frozen in pairs or individually in freezer-safe containers. Make sure to top each with some extra sauce. When ready to eat, let thaw in the refrigerator overnight, then either transfer either to a baking dish to reheat in the oven or to a microwave-safe plate for reheating in the microwave, depending on your preference.