Preheat the oven to 375°F (190°C).
Slice the zucchinis in half lengthwise and scoop out the seeds to create the boat shape.
Drizzle the zucchini halves with olive oil, and season with salt and pepper. Place them on a baking sheet.
In a bowl, mix ricotta cheese, cooked spinach, garlic, oregano, basil, salt, and pepper.
Stuff the zucchini boats with the ricotta-spinach mixture. Optionally top with mozzarella cheese.
Bake for 20-25 minutes, or until the zucchini is tender and the cheese is melted and golden.
Let rest for 5 minutes before serving.