Prep the peppers. Heat your oven to 375°F (190°C). Slice the tops off the peppers and remove seeds and membranes. If they wobble, shave a thin slice off the bottom so they stand upright. Place them in a baking dish that holds them snugly.

Soften the peppers. Drizzle with 1 tablespoon olive oil and a pinch of salt. Add the chicken broth to the bottom of the dish, cover tightly with foil, and bake for 15 minutes. This head start keeps the peppers tender later.

Sauté the aromatics. While peppers bake, heat the remaining olive oil in a large skillet over medium. Add onion and zucchini with a pinch of salt. Cook 5–6 minutes until soft and lightly golden. Stir in garlic and cook 30 seconds until fragrant.

Cook the chicken. Add ground chicken to the skillet. Season with salt, black pepper, paprika, Italian seasoning, and red pepper flakes if using. Break it up with a spoon and cook until no longer pink, about 5–7 minutes.

Build the filling. Stir in tomato paste and cook 1 minute. Add crushed tomatoes and simmer 2–3 minutes to thicken slightly. Fold in cooked rice, 1/2 cup mozzarella, and Parmesan. Taste and adjust seasoning. The mixture should be savory and slightly saucy—not dry.

Stuff the peppers. Remove peppers from the oven and uncover. Spoon the filling into each pepper, pressing down lightly so they’re well packed and mounded at the top.

Bake. Cover with foil and bake 15 minutes. Uncover, sprinkle the remaining 1/2 cup mozzarella on top, and bake another 10–12 minutes until the cheese is melted and the peppers are fork-tender.

Finish and serve. Let the peppers rest 5 minutes. Spoon any juices from the pan over the tops. Garnish with chopped parsley and serve warm.