Preheat your oven to 350°F (175°C) and position the oven rack in the middle. Line two cookie sheets with parchment paper.

In a large mixing bowl, whip egg yolks and half of the granulated sugar until pale and fluffy, then add vanilla extract and optional lemon zest.

In a separate bowl, beat egg whites, gradually adding remaining sugar until stiff peaks form.

Fold the whipped egg whites into the yolk mixture carefully not to deflate them.

Whisk together the flour, cornstarch, and a pinch of salt, then fold into the batter until smooth.

Fill a piping bag with the batter and pipe 3-inch long fingers onto the prepared sheets, leaving space between each.

Dust the piped cookies with powdered sugar before baking.

Bake for 12-15 minutes until they are puffed and lightly golden, then cool completely on a wire rack.