Wash and dry the zucchini. Cut lengthwise into slices 1/3-inch thick. Place the zucchini slices in a colander, sprinkle with salt and set aside to drain for 2 hours.
In a large saucepan, heat the olive oil over medium heat. Place the drained zucchini slices in the pan and cook gently until golden brown on both sides, about 3 minutes per side, being careful not to burn the slices. Set aside.
In another saucepan, bring the vinegar and sugar to a boil over high heat. Add a pinch of pepper flakes and a pinch of salt.
Place the zucchini slices flat in a shallow bowl, with the garlic slices, basil and parsley scattered throughout. Pour the vinegar over the zucchini slices and let marinate, covered, for at least 24 hours before serving.
Recipe courtesy of Mario Batali