I usually make the recipe out of the book that came with the iron (shut up) but here is an alternative, again from the King Arthur Flour Baking Banter Blog.
No Italian holiday is complete without crisp, buttery pizzelle. Read our blog about these cookies, with additional photos, at Bakers' Banter.
3 large eggs
3/4 cup sugar
3/8 teaspoon salt
1 teaspoon vanilla
1 3/4 cups King Arthur Unbleached All-Purpose Flour
2 teaspoons baking powder
1/2 cup melted butter
1) Beat the eggs, sugar, salt, and vanilla until well combined.
2) Stir in the flour and baking powder, mixing until smooth.
3) Add the melted butter, again mixing till smooth; the batter will be thick and soft.
4) Heat your pizzelle iron. As it heats, the batter will stiffen.
5) Cook the pizzelle according to the instructions that came with your iron. In general, they'll take between 45 seconds and 2 1/2 minutes to brown.
6) Remove the pizzelle from the iron, and cool on a rack. If desired, use a pair of scissors to trim any ragged edges.
7) Dust cooled pizzelle with confectioners' sugar, if desired.