Meringue Mushrooms

For the meringue: Preheat oven to 200°. Combine sugar and 1⁄4 cup water in a small saucepan, cover, and bring to a boil over medium-high heat, swirling pan several times until sugar has dissolved, 1–2 minutes. Uncover pan and continue to boil until syrup reaches softball stage or 236° on a candy thermometer, about 4 minutes more. Put egg whites in the bowl of a standing mixer fitted with a whisk and beat on medium speed until frothy, then add cream of tartar and salt. Gradually increase speed to high and beat until soft peaks form, about 30 seconds. Slowly pour in sugar syrup while continuing to beat until whites cool to room temperature and become thick and shiny, about 10 minutes. Stir in vanilla.

To make meringue mushrooms: Use a rubber spatula to transfer meringue to a pastry bag fitted with a 1⁄4" plain pastry tip. Hold pastry tip perpendicular to a parchment paper-lined baking sheet and pipe meringue into the shapes of mushroom caps and stems of various sizes, then set aside for 5 minutes. Lightly moisten a fingertip in cold water and smooth out any "tails" left behind on mushroom caps. Bake meringues for 1 1⁄2 hours.

Turn off oven and allow meringues to rest in oven until dry and crisp, about 1 hour. Bore a small, shallow hole in center of underside of each mushroom cap with the tip of a paring knife. "Glue" stems to caps by dipping tips of stems into Chocolate Ganache Icing, then sticking into holes in caps. Sift a little cocoa powder on tops of caps. Meringues can be stored in an airtight container at room temperature for several days.