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.