Mont-Blanc

Prepare the meringue 4 hours before serving: Position racks at the upper and lower thirds, preheat the oven to 225°F, and line 2 baking sheets with parchment paper.

In a small bowl, combine the granulated sugar and powdered sugar. In the bowl of a stand mixer fitted with the whisk attachment, combine the egg whites, cream of tartar, and salt. Beat the egg whites on low and then medium speed, until they form medium peaks. Whisk in one third of the sugar mixture and continue beating on medium speed as you sprinkle in the remaining sugar, a little bit at a time. The meringue is ready when it is glossy and forms stiff peaks; this will take about 10 minutes.

Transfer it to a piping bag fitted with a ½-inch plain or star tip. Working in a tight zigzag, pipe the meringue onto one of the baking sheets to form 4 long rectangles about 1½ × 12 inches.