Brown the Sausage: In a medium skillet over medium heat, cook the Italian sausage, breaking it apart with a spoon, until it's browned and cooked through.
Drain any excess grease, then stir in the marinara sauce.
Set the mixture aside.
Prep the Oven and Peppers: Preheat your oven to 375°F / 190°C.
Slice the bell peppers in half lengthwise and remove the stems, seeds, and white membranes.
Arrange the pepper halves, cut-side up, on a parchment-lined baking sheet.
Stuff and Top: Spoon the sausage and marinara mixture evenly into each pepper half.
Top generously with shredded mozzarella, place two slices of pepperoni on each, and finish with a light sprinkle of Italian seasoning.
Bake to Perfection: Bake for 20-25 minutes, or until the peppers are tender-crisp and the cheese is melted and bubbly.
Garnish with grated Parmesan cheese before serving hot.
