Use these cookies to top off our Individual Chocolate-Espresso Charlottes.
Preheat oven to 200 degrees. Whisk egg whites and sugar in a heatproof mixer bowl set over a pan of simmering water until sugar dissolves and mixture registers 140 degrees on an instant-read thermometer, 2 to 3 minutes.
Transfer bowl to mixer, and whisk on medium-high speed until mixture has cooled and formed stiff, glossy peaks, 6 to 8 minutes. Reduce speed to low and add coffee extract. Raise speed to medium, and whisk until combined, scraping down sides of bowl to ensure uniform coloring.
Fill a pastry bag fitted with a 7/16-inch star tip (such as Ateco #825) with meringue. Pipe 1-inch meringues onto parchment-lined baking sheets, spacing 1 inch apart.
Bake until hard to the touch but not cracked or browned, 2 to 3 hours. Let cool. Meringues can be stored in an airtight container in a cool, dry place for up to 2 weeks.