Preheat the oven: Set to 400°F (200°C). Lightly oil a baking dish large enough to hold the zucchini halves snugly.

Prep the zucchini: Trim the ends and slice each zucchini lengthwise. Use a spoon to scoop out the center, leaving a 1/4-inch thick shell. Chop the scooped flesh and set it aside.

Season the boats: Brush the insides with 1 tablespoon olive oil and sprinkle with salt and pepper. Place them cut-side up in the baking dish.

Sauté aromatics: Warm the remaining 1 tablespoon olive oil in a skillet over medium heat. Add onion and bell pepper; cook 4–5 minutes until softened. Stir in garlic; cook 30 seconds.

Add zucchini flesh: Add the chopped zucchini centers and a pinch of salt. Cook 3–4 minutes to reduce moisture.

Build the filling: Stir in tomato paste, Italian seasoning, smoked paprika, and red pepper flakes. Cook 1 minute. Add chicken, chicken broth, and half the Parmesan. Simmer 2–3 minutes, stirring, until juicy but not watery. Adjust salt and pepper.

Fill the boats: Spoon the chicken mixture into each zucchini shell, mounding slightly. Top with mozzarella and the remaining Parmesan.

Bake: Cover loosely with foil and bake 15 minutes. Uncover and bake 8–12 minutes more, until zucchini is tender and cheese is melted and golden.

Finish and serve: Let rest 5 minutes. Sprinkle with chopped parsley or basil and a light squeeze of lemon for brightness. Serve warm.