Chocolate Chunk-Walnut Meringue Cookies
Equipment: Parchment paper; stand mixer
To make ahead: Store in an airtight container at room temperature for up to 5 days.
Tip: To get the most volume from beaten egg whites, it's best to start with the whites at room temperature. Submerge the eggs in their shells in a bowl of lukewarm (not hot) water for about 5 minutes before using.