Preheat your oven to 350°F and line two baking sheets with parchment paper.

In a clean, dry bowl, beat egg whites until soft peaks form. Gradually add half of the sugar and continue beating until stiff peaks are achieved.

In a separate bowl, whisk together egg yolks, the remaining sugar, and vanilla extract until the mixture is pale and slightly thickened.

Carefully fold the yolk mixture into the beaten egg whites.

Sift the flour and cornstarch over the egg mixture and gently fold until just combined, being careful not to deflate the mixture.

Transfer the batter to a piping bag fitted with a 1/2 inch round tip and pipe 3-inch long fingers onto the prepared baking sheets, spaced about 1 inch apart.

Dust the piped ladyfingers with powdered sugar and bake for 12-15 minutes, or until they are lightly golden and firm to the touch.

Allow the ladyfingers to cool on the baking sheets for a few minutes before transferring them to a wire rack to cool completely.