Preheat oven to 160°C or 140°C fan. Arrange tomato on a baking tray and drizzle over 1 tablespoon of oil. Sprinkle with thyme and season to taste. Roast for 15 minutes, until tender. Set aside.
Heat remaining oil in a 22cm frying pan on medium. Cook zucchini slices for 5 minutes, until tender. Arrange tomato and olives in frying pan. Pour in egg and continue to cook for 5 minutes. Pull in cooked edges occasionally with a fork, so uncooked egg runs to the sides. When base is golden and top almost set, scatter with parsley. Place under a preheated hot grill for 2-3 minutes, until top is set and golden.
Slide frittata onto a serving plate and cut into wedges. Serve sprinkled with extra parsley.