Preheat the oven to 375 degrees F.

Pour about ¼ of the jar of marinara sauce into the bottom of a 9x13 baking dish, and spread so that it evenly coats the bottom of the dish.

Use a spoon to scoop out the seeds of each halved zucchini to create a “boat”. Lay the hollowed zucchini skin-side down on top of the sauce in the prepared baking dish. Drizzle with 2 tbsp olive oil and sprinkle with ½ tsp kosher salt.

Transfer to the oven and bake for 15 minutes, so that the zucchini is slightly tender.

Meanwhile, in a large bowl, mix together the chicken, parmesan, parsley, garlic, crushed red pepper, and the remaining bottle of marinara sauce. Toss to combine.

When the zucchini is tender, remove from the oven. Fill the zucchini boats with the chicken mixture. Then, sprinkle the top with the mozzarella cheese.

In a small bowl, combine the gluten-free panko and the remaining tablespoon of extra virgin olive oil and toss until well combined. Sprinkle over the top of the zucchini boats until evenly coated.

Transfer back to the oven and continue to bake until the cheese and panko are golden brown, about 10 more minutes.