Swiss Meringue Letters for Hexagonal Wedding Cake

In the heatproof bowl of an electric mixer, combine egg whites and sugar. Set bowl over a pot of gently simmering water, and whisk constantly until the mixture is very warm to the touch and sugar is dissolved, about 3 minutes (test by rubbing between your fingers to detect any graininess). Attach bowl to mixer stand. Using the whisk attachment, beat on medium-high speed until mixture is cool and forms stiff, glossy peaks, 10 to 15 minutes.

Line 2 baking sheets with parchment or wax paper. Attach a #18 Ateco open-star tip to a 12-inch pastry bag fitted with a plastic coupler. Fill bag halfway with Swiss meringue. Working quickly, pipe the letter of your choice, about 2 1/2 inches long and 2 inches wide, onto the lined baking sheets. You will need only 15 letters for the cake, but we recommend making at least 30, as they are very fragile. Refill your bag with meringue, as needed, stirring meringue before refilling bag. Let piped letters sit at room temperature until completely dry, usually about 1 day, or bake in a 200 degrees oven until completely dry, 2 to 4 hours. Transfer cooled, dried meringues to an airtight container; do not let them sit in the open air. Store at room temperature until ready to use, up to 2 days. If meringues begin to absorb moisture and feel sticky, dry briefly in a 200 degrees oven again.