Preheat the oven to 400°F (200°C).
Line a baking sheet or a 9x13-inch baking dish with parchment for easy cleanup.
Prep the peppers: Brush the cut sides with 1 tablespoon olive oil and a light sprinkle of salt. Place them cut-side up on the baking sheet. Par-bake for 10 minutes to soften slightly.
This helps them cook evenly once stuffed.
Crisp the bacon: Heat a large skillet over medium heat. Add chopped bacon and cook until browned and crisp, about 6–8 minutes. Use a slotted spoon to transfer bacon to a plate, leaving about 1–2 tablespoons bacon fat in the pan.
Cook the aromatics: Add onion to the skillet and cook until translucent, 3–4 minutes.
Stir in garlic and cook 30 seconds until fragrant.
Brown the chicken: Add ground chicken to the skillet. Season with smoked paprika, oregano, chili flakes (if using), salt, and pepper. Cook, breaking it up, until no longer pink, 5–6 minutes.
Add moisture and richness: Stir in the sugar-free marinara (or crushed tomatoes) and cook 1–2 minutes to reduce slightly.
Cut the heat to low and mix in cream cheese until smooth and creamy.
Fold in the bacon and cheeses: Return the bacon to the pan. Add half the mozzarella and half the Parmesan; stir to combine. Taste and adjust salt and pepper.
The mixture should be thick and scoopable.
Stuff the peppers: Spoon the chicken-bacon mixture evenly into the par-baked pepper halves. Top with the remaining mozzarella and Parmesan.
Bake: Return to the oven and bake for 15–18 minutes until the peppers are tender and the cheese is melty and lightly browned.
Finish and serve: Let rest 5 minutes. Garnish with chopped parsley or chives.
Add a small squeeze of lemon if you like a bright finish. Serve warm.