Separate the egg whites from the yolks carefully, making sure no yolk gets into the whites. Place the egg whites in a clean, dry mixing bowl and transfer to the freezer for exactly 10 minutes. This brief chill makes the whites more stable and easier to whip into a fine, glossy meringue.

Remove the chilled egg whites from the freezer. Add 4 drops of lemon juice, 25g granulated sugar, and 5g cornstarch. Using an electric hand mixer, whip the egg whites until they reach stiff peaks. You'll know they're ready when you lift the beaters and the meringue stands up straight with a firm, sharp tip that doesn't droop.

Add the egg yolks to the whipped meringue. Mix on low speed just until the yolks are roughly incorporated. Don't overmix here—you want the mixture to remain light and airy, with a pale yellow colour throughout.

Sift 60g of cake flour directly over the egg mixture. Using a spatula, fold gently until just combined. Use a cutting motion through the center, scrape along the bottom, and turn the bowl as you go. Stop as soon as the flour disappears—overmixing will deflate the batter and result in dense, flat ladyfingers.

Transfer the batter to a piping bag fitted with a round tip (or simply snip the end off a disposable piping bag). Line a baking tray with parchment paper and pipe the batter into finger-length strips, about 8-10cm long. Leave a little space between each one, as they'll spread slightly during baking.

Preheat your oven according to your oven type. For a convection (fan-forced) oven, bake at 150℃ for 25 minutes. For a conventional (standard) oven, bake at 170℃ for 25 minutes. The ladyfingers are ready when they're golden around the edges, crisp to the touch, and lift easily off the parchment paper.

Let the ladyfingers cool on the baking tray for 5 minutes, then transfer them to a wire rack to cool completely. They will continue to crisp up as they cool.