You can freeze any leftover dough to use later, but you may not be able to resist making the whole batch of these chocolatey wafers.
Place a 12-by-16-inch piece of parchment on a work surface. Spoon dough down center. Fold parchment over dough. Using a ruler, roll and press dough into a tight log. Wrap in parchment; chill at least 1 hour.
Heat oven to 350 degrees. Line two baking sheets with parchment. Unwrap log, and slice into 1/8-inch-thick rounds. Place rounds on baking sheets, spaced 1 1/2 inches apart.
Bake wafers until firm to the touch, 20 to 25 minutes. Transfer wafers to a wire rack to cool. Bake or freeze remaining dough. Store baked cookies in an airtight container for up to 2 weeks.