Preheat oven to 350°F. Use a small paring knife to cut around the tops of the peppers at a slight downward angle. Remove the tops, then tap out seeds and pull out veins. If the bottoms don’t sit flat, slice off a tiny bit. Place peppers in a baking dish so they fit close together, which helps them stay upright and steam as they bake.
Heat olive oil in a large skillet over high heat. Add onion and garlic and cook, stirring, until lightly golden, about 3 minutes. Push to the edges of the skillet, then add sausage to the center. Let sear for 1 minute per side before breaking it up. Cook and crumble until browned through. Stir in tomato paste and seasonings. Cook for 2 minutes, stirring constantly, until fragrant.
Stir in rice, Worcestershire, broth, and marinara. Bring to a simmer, then cover, reduce heat to medium-low, and cook for 13–15 minutes, until rice is just tender. The filling should be slightly saucy, not dry (add a splash of broth if needed). Taste and adjust seasonings.
Spoon half the filling into the peppers. Add half the cheese, then top with remaining filling. Place pepper lids back on. Pour 1/2 cup water into the bottom of the baking dish. Cover tightly with foil and bake for 45 minutes.
Remove foil and pepper lids. Sprinkle with the remaining cheese and bake uncovered for 5–8 minutes, until melted. Serve hot with parsley, and grate fresh Parmesan on top with a microplane if desired.
Notes
Note 1: Use red, orange, or yellow peppers. Choose large, evenly sized ones with four bumps on the bottom so they stand upright. This filling usually makes enough for 5–6 peppers.Note 2: Basmati rice works especially well. Long-grain white rice is the next best option; other varieties are not recommended.Note 3: I like using Rao’s marinara best, but you can use fire-roasted diced tomatoes instead if desired.Storage: Keep cooked peppers in an airtight container in the fridge for up to 4 days. For longer storage, wrap peppers individually and place in a freezer-safe bag for up to 3 months. Reheat in the oven until warmed through.