1. Preheat oven to 350F. Line a 12-cup muffin tin with paper liners.

2. In a small bowl, sift together cake flour and 1/4 cup superfine sugar.

3. In a large bowl, beat room-temperature egg whites until foamy, then add in cream of tartar and salt. Gradually add in the remaining 1/2 cup of superfine sugar while the mixer is on high speed, beating the egg whites to soft peaks.With a rubber spatula add in the vanilla and lemon zest, do this very gently!

4. Fold in flour mixture, adding it in two or three additions.

5. Divide evenly into prepared muffin tins. Fill them pretty full.

6. Bake for 16-18 minutes, until golden brown. The tops will spring back when lightly touched.

7. Cool on a wire rack.

To make the lemon glaze:

Combine confectioners sugar with lemon juice. Whisk until smooth. Drizzle on top of cooled cupcakes.