Preheat and prep. Heat your oven to 400°F (200°C). Line a baking sheet or a large baking dish with parchment for easy cleanup.

Prepare the zucchini boats. Trim the ends, slice each zucchini lengthwise, and use a spoon to scoop out the centers, leaving about 1/4-inch walls. Reserve about 1/2 cup of the chopped zucchini flesh and discard the rest or save for another use.

Season the boats. Brush the cut sides with 1 tablespoon olive oil. Sprinkle lightly with salt and pepper. Arrange cut-side up on the baking sheet.

Par-bake the zucchini. Bake for 8–10 minutes until just starting to soften. This helps them cook through without getting watery later.

Make the filling. While the boats bake, heat the remaining 1 tablespoon olive oil in a skillet over medium heat. Add garlic and reserved chopped zucchini flesh. Sauté for 2–3 minutes until fragrant and softened.

Build the chicken mixture. Stir in the cooked chicken, 1 cup of marinara, Italian seasoning, onion powder, red pepper flakes (if using), and a pinch of salt and pepper. Warm through for 2–3 minutes. The mixture should be thick and saucy, not watery.

Fill the boats. Spoon the chicken mixture evenly into the par-baked zucchini shells. Top each with the remaining 1/2 cup marinara in small dollops so it doesn’t get soggy.

Add the cheese. Sprinkle mozzarella over the tops, then dust with Parmesan for that classic chicken Parm finish.

Bake to bubbly. Return to the oven for 12–15 minutes, until the cheese is melted and the zucchini is tender when pierced with a fork.

Optional broil. For extra color, broil on high for 1–2 minutes. Watch closely so it doesn’t burn.

Finish and serve. Let rest for 5 minutes. Garnish with chopped basil or parsley and a little extra Parmesan. Serve warm.