01 - Preheat the oven to 400°F. Line a baking dish with parchment paper or lightly grease it.
02 - Slice the zucchini in half lengthwise. Using a spoon, scoop out the centers to create boats, leaving about 1/4-inch thick shells. Reserve the scooped flesh and chop it finely.
03 - Heat olive oil in a large skillet over medium heat. Add onion and cook until softened, about 3 minutes. Add garlic and cook for 1 minute more.
04 - Add ground turkey, breaking it up with a spoon. Cook until browned and cooked through, about 5–7 minutes.
05 - Stir in the chopped zucchini flesh, red bell pepper, and cherry tomatoes. Cook for 4–5 minutes until vegetables are tender and moisture evaporates.
06 - Remove from heat. Stir in the pesto, salt, and pepper to taste.
07 - Arrange the zucchini boats in the prepared baking dish. Fill each boat generously with the turkey-pesto mixture.
08 - Sprinkle mozzarella and Parmesan cheese evenly over the stuffed zucchini.
09 - Bake for 18–20 minutes, until the zucchini is tender and the cheese is melted and golden.
10 - Let cool for 5 minutes before serving.