Though you should feel free to eat or serve these adorable mushrooms as you see fit, they are the traditional decoration for a Bûche de Noël. Please read About Baked Meringue and Dacquoise.
Preheat the oven to 200°F. Line 2 baking sheets with parchment paper.
Prepare:
Scrape the meringue into a large pastry bag fitted with a ½-inch plain tip. Pipe thin pointed “kiss” shapes about 1 inch tall onto the baking sheets to make mushroom stems. Pipe round button shapes in different sizes to make mushroom caps. Use a lightly moistened or damp finger to smooth the tops of the caps if necessary. Dust lightly with:
Bake until crisp and completely dry, about 2 hours.
Let cool overnight in the turned-off oven.
Melt in a double boiler or a heatproof bowl set over a pan of barely simmering water:
Use a sharp knife to cut off and discard the pointed ends of the meringue stems. Spread a little melted chocolate on the flat side of each meringue mushroom cap and attach the stems while the chocolate is still soft. Let stand until the chocolate is set. The mushrooms can be stored in an airtight container for up to 4 weeks.