01 - Preheat oven to 400°F. Line a baking dish with parchment paper or lightly grease it.
02 - Slice each zucchini in half lengthwise. Using a spoon, carefully scoop out the centers to create boats, leaving a 1/4-inch border intact. Reserve 1/2 cup of the scooped flesh and finely chop it; set aside.
03 - Arrange zucchini boats cut side up in the prepared baking dish. Brush with 1 tbsp olive oil and season with a pinch of salt and pepper.
04 - Heat the remaining 1 tbsp olive oil in a large skillet over medium heat. Add the diced onion and cook for 3 minutes until softened. Stir in the minced garlic and sauté for 1 minute until fragrant.
05 - Add the ground turkey to the skillet, breaking it apart with a spoon. Cook for 6 to 7 minutes until evenly browned and cooked through.
06 - Stir in the reserved chopped zucchini flesh and chopped spinach. Cook for 1 to 2 minutes until the spinach has wilted completely.
07 - Remove the skillet from heat. Stir in the basil pesto, 1 tbsp of the chopped basil, and half of the chopped parsley. Season with the remaining salt, black pepper, and crushed red pepper flakes.
08 - Spoon the turkey filling evenly into each zucchini boat. Sprinkle the shredded mozzarella and grated Parmesan over the tops.
09 - Bake for 20 minutes, or until the zucchini is fork-tender and the cheese is bubbly and lightly golden.
10 - Remove from the oven and garnish with the remaining fresh basil and parsley. Serve immediately while hot.