1. Preheat the oven to 350 F (180°C).
2. Make a long, lengthwise slit in each zucchini that reaches about halfway through. (Do not cut the zucchini all the way through). Stuff each zucchini with the sliced garlic.
3. Transfer the tomatoes to an oven-safe casserole dish, and nestle the zucchini between the tomatoes. Drizzle the olive oil over the zucchini and tomatoes.
4. Sprinkle the salt, black pepper, and 1 tablespoon of the parsley over the zucchini and tomatoes. Turn the zucchini gently so they are covered in the olive oil.
5. Transfer to the oven and cook for 1 hour 15 minutes or until the skins are soft and the edges have browned.
6. Carefully remove the dish from the oven and sprinkle the remaining parsley and sea salt, if using, over the top. Store covered in the refrigerator for up to 3 days.
TIP: Traditionally, this dish is enjoyed at room temperature and served with bread and feta.