Heat a nonstick pizzelle iron. In a large bowl, sift together all-purpose flour, baking powder, and salt; set aside.
In a large bowl, whisk eggs. Slowly add sugar, and continue mixing until well blended. Whisk in vanilla and lemon extracts. Slowly add the cooled butter in a steady stream, whisking continuously until the batter is smooth.
Slowly add the flour mixture, and keep whisking until the flour is completely incorporated into the batter. Do not overmix.
Fill a pastry bag fitted with a #4 Ateco plain tip with batter. Pipe 1 1/2 tablespoons batter in a circle around the center of each pattern on the heated pizzelle iron. Close the iron and seal with the clasp. Cook until golden brown, 50 to 60 seconds. Using a small spatula, remove pizzelles, and place on a wire rack to cool.
When pizzelles are cool, trim to shape, if necessary. Spread half of the cookies with 1 1/2 tablespoons cooled Caramel Sauce, and sandwich together with a plain cookie, pressing gently to evenly spread caramel. Store in an airtight container for up to 3 days.