In a medium mixing bowl, beat the eggs. Gradually add the flour and sugar alternatively with the milk and water, beating with an electric mixer or whisk until smooth. Beat in the melted butter.
Combine the ingredients in the blender jar. Blend for about 1 minute. Scrape down the sides with a rubber spatula and blend for another 15 seconds or until smooth. Do not blend too quickly or the batter may become too bubbly.
Refrigerate the batter for at least 1 hour. Cook on an upside-down griddle or in a traditional crepe pan.