Rinse zucchini and cut into small pieces or slices. Peel garlic and chop finely. Mix zucchini with thyme and garlic and fry in hot oil in a frying pan for 4-5 minutes. Season with salt and pepper.
Whisk eggs with whipping cream and season with salt and pepper. Pour over the zucchini, cover and cook over low heat, 8-10 minutes. Using a large plate, flip the frittata over, place back in the frying pan, sprinkle with Parmesan cheese and cook covered 3-5 minutes longer. Transfer to a platter and serve garnished with thyme.