Sifting the flour mixture thoroughly three times incorporates the powdered sugar for a light, tender cupcake. This also allows multiple kitchen helpers to give sifting a try. To help with cleanup, place a kitchen towel underneath the sifter and mixing bowl; shake off any mess into the sink or trash can when you're done.
2 ounces cake flour (about 1/2 cup)
3/4 cup powdered sugar
3/4 cup egg whites (about 5 large eggs)
3/4 teaspoon cream of tartar
1/8 teaspoon salt
1/2 cup granulated sugar
1/2 teaspoon vanilla extract
2 teaspoons grated lemon rind
1/4 cup butter, softened
2 cups powdered sugar
1 tablespoon 1% low-fat milk
2 tablespoons freshly squeezed lemon juice
Fresh raspberries (optional)
How to Make It
Preheat oven to 350°.
Place 16 paper muffin cup liners in muffin cups. Set aside.
Weigh or lightly spoon cake flour into a dry measuring cup; level with a knife. Sift together flour and 3/4 cup powdered sugar into a medium bowl; repeat procedure twice.
Beat egg whites, cream of tartar, and salt with a mixer at high speed until frothy. Add 1/2 cup granulated sugar, 1 tablespoon at a time, beating until stiff peaks form. Sprinkle flour mixture over egg white mixture, 1/4 cup at a time; fold in after each addition. Fold in vanilla and rind. Divide batter evenly among prepared muffin cups.
Bake at 350° for 18 minutes or until lightly browned. Remove from pan; cool completely on a wire rack.
To prepare frosting, beat butter with a mixer at high speed until fluffy. Gradually add 2 cups powdered sugar, beating at low speed just until blended. Add milk and lemon juice; beat until spreading consistency. Spread 2 tablespoons lemon frosting over each cupcake. Garnish with fresh raspberries, if desired.