Preheat your oven to 375°F (190°C) and line a baking dish with parchment paper or lightly grease it with olive oil.
Slice the zucchinis in half lengthwise and scoop out the center using a spoon, creating small boats. Reserve the scooped-out flesh for later use.
In a skillet over medium heat, warm the olive oil and sauté the garlic until fragrant, about 1 minute.
Add the reserved zucchini flesh, chopped spinach, and cherry tomatoes to the skillet. Cook until the spinach is wilted and the tomatoes are slightly softened, about 3-4 minutes.
Stir in the cooked quinoa, mozzarella cheese, Italian seasoning, salt, and pepper. Mix everything until well combined.
Stuff each zucchini boat generously with the quinoa and vegetable mixture.
Place the stuffed zucchinis in the prepared baking dish and sprinkle grated Parmesan cheese over the top of each boat.
Bake in the preheated oven for 20-25 minutes, or until the zucchinis are tender and the cheese is bubbly and golden.
Once baked, remove from the oven and let cool slightly before serving. Garnish with fresh basil leaves.
Notes
Feel free to customize the filling with your favorite vegetables.