Wash the zucchini, wipe them dry and cut them into 1/3 inch thick slices, with their skins. Place the zucchini in 3 quarts of salted boiling water and cook for 15 to 18 minutes. Drain them in a colander. Using a ladle, press the zucchini to extract all the excess water. Spread them in a buttered ovenproof dish. Squash them with a fork. In a bowl, beat the eggs as for an omelet, add the cream, grated Swiss cheese, season with salt and pepper and sprinkle with some ground nutmeg. Pour the mixture over the zucchini, stir and bake the gratin in a hot oven for 15 minutes.
