Prep the oven and pan: Preheat oven to 400°F (200°C). Lightly grease a 9x13-inch baking dish.

Prepare the zucchini boats: Trim the ends and slice each zucchini in half lengthwise. Use a spoon to scoop out the center, leaving a 1/4-inch border to form boats. Reserve about 1/2 cup of the chopped zucchini flesh, finely diced. Brush the boats with olive oil and season with salt and pepper. Place them cut-side up in the baking dish.

Par-bake the zucchini: Bake for 10–12 minutes until just tender but not fully soft. This helps avoid watery results later. Remove and set aside.

Make the Alfredo base: In a skillet over medium heat, melt the butter. Add garlic and sauté 30–60 seconds until fragrant. Stir in the reserved diced zucchini flesh and cook 2–3 minutes to soften.

Build the sauce: Lower heat and whisk in the heavy cream and cream cheese. Stir until smooth and slightly thickened, 2–3 minutes. Add Parmesan, stirring until melted. Season with salt, pepper, and optional Italian seasoning or red pepper flakes.

Add the chicken: Fold in the cooked chicken and any optional greens (spinach or broccoli). The mixture should be thick and creamy; if too thick, add a splash more cream. If too thin, simmer 1–2 minutes to reduce.

Fill the boats: Spoon the chicken Alfredo mixture into each zucchini boat, packing it in evenly. Sprinkle mozzarella and a little extra Parmesan over the top.

Bake to bubbly: Return the dish to the oven and bake 12–15 minutes, until the cheese is melted and golden in spots and the zucchini is tender.

Finish and serve: Let rest 5 minutes. Garnish with chopped parsley. Taste and adjust salt and pepper if needed. Serve warm.