You must have prepared idli-dosa batter before you start with this recipe (please refer to the detailed post on the batter) . I typically use a day or two old batter to make these waffles. Transfer 2 cups of batter to a bowl. Now add little water to thin it out, you would need around 1 to 2 tablespoons water here but it should depend on how thick or thin your batter is to begin with. I added 2 tablespoons water here and mixed well.