In a mixing bowl, whisk together all the ingredients (including the optional herbs or spices) until smooth. Let the batter rest covered for at least an hour, or until you need it. (You could mix it in the morning and make it in the evening.)
Preheat a waffle iron on high, brushing it with oil. Spoon out enough batter for it to spread across the waffle iron, then close it and cook until the socca becomes golden and crisp. Eat as soon as possible.