01 - Preheat the oven to 400°F. Line a baking dish with parchment paper or lightly grease it with olive oil.
02 - Slice the zucchini in half lengthwise. Using a spoon, scoop out the pulp, leaving a 1/4-inch shell. Reserve the pulp and chop it finely.
03 - Heat olive oil in a large skillet over medium heat. Add the onion and cook for 2 minutes until softened. Add the garlic and cook for 1 additional minute until fragrant.
04 - Add the ground turkey to the skillet, breaking it apart with a spoon. Cook for 5 to 7 minutes until browned and cooked through completely.
05 - Stir in the chopped zucchini pulp, spinach, salt, black pepper, and red pepper flakes. Cook for 3 to 4 minutes until the spinach is wilted and any excess liquid has evaporated.
06 - Remove the skillet from heat and stir in the pesto, mixing thoroughly to coat all ingredients evenly.
07 - Place the zucchini halves in the prepared baking dish. Fill each boat generously with the turkey, spinach, and pesto mixture.
08 - Sprinkle the mozzarella and Parmesan cheeses evenly over the filled zucchini boats.
09 - Bake for 20 to 25 minutes until the zucchini shells are tender and the cheese is golden and bubbly.
10 - Remove from the oven, garnish with fresh basil and parsley, and serve warm.