Let egg whites stand at room temperature for 30 minutes.

Sift together flour and 1/2 cup sugar three times; set aside.

Add cream of tartar, vanilla and salt to egg whites.

Beat on medium speed until soft peaks form.

Gradually add remaining sugar, about 2 tablespoons at a time, beating on high until stiff glossy peaks form and sugar is dissolved.

Gradually fold in flour mixture, about 1/2 cup at a time.

Fold in blueberries and lemon peel.

Fill paper-lined muffin cups three-fourths full.

Bake at 375°F (190°C) for 14-17 minutes or until cupcakes spring back when lightly touched.

Immediately remove from pans to wire racks to cool completely.

In a small bowl, whisk confectioners' sugar and lemon juice until smooth.

Brush over cupcakes.

Let stand until set.