1 1/2 cups confectioners sugar, plus more for topping", "1/4 teaspoon salt", "11 large egg whites, at room temperature", "1 1/2 teaspoons cream of tartar", "1 cup granulated sugar", "1 teaspoon vanilla extract", "1 teaspoon finely grated lime zest", "3 tablespoons finely grated peeled ginger", "3 half pints raspberries", "1/3 cup granulated sugar", "1/2 teaspoon finely grated lime zest", "1 teaspoon fresh lime juice
Instructions
Make the cake: Preheat the oven to 350 degrees F. Sift the flour, confectioners' sugar and salt onto a sheet of parchment paper.
Sift again, then set aside.
Beat the egg whites in a large bowl with a mixer on medium speed until frothy.
Add the cream of tartar and beat until soft peaks form, about 5 minutes.
Gradually beat in the granulated sugar, about 1 tablespoon at a time, then increase the speed to medium high and continue beating until stiff, shiny peaks form, 12 to 15 minutes.
Add the vanilla, lime zest and ginger and beat a few seconds to combine.
Sprinkle one-quarter of the flour mixture over the egg mixture and gently fold with a rubber spatula.
Fold in the remaining flour mixture in 3 additions.
Transfer the batter to an ungreased 10-inch tube pan.
Bake until the cake feels springy and a toothpick inserted into the center comes out clean, 40 to 50 minutes.
Invert the pan onto a funnel or the neck of a bottle and cool completely.
Loosen the edges with a small knife, tap the sides of the pan against the counter and unmold.
Make the sauce: Puree 2 half pints raspberries in a blender with 2 tablespoons water, the granulated sugar, lime zest and lime juice.
Strain to remove the seeds.
Top the cake with confectioners' sugar, the sauce and the remaining raspberries.