Sourdough Ladyfingers

Prepare two baking sheets with parchment paper. Preheat the oven to 350ºF (177º C).
Using an electric hand mixer or hand whisk to beat the three egg yolks, 50g of sugar, salt, vanilla, and sourdough discard in a medium mixing bowl.
Set aside as you beat the egg whites and clean and dry the beaters.
3 Eggs, 100 g Granulated Sugar, ½ tsp Vanilla Extract, ¼ tsp Kosher Salt, 50 g Sourdough Discard
In a clean, dry bowl, beat the egg whites for a couple of minutes until frothy. While beating, slowly pour in the other 50g of granulated sugar. Beat until they form stiff peaks and dramatically increase in size.
Pour the egg yolk mixture into the egg whites and use a spatula to gently fold together until only a few streaks remain.
Sift the flour and cornstarch on top and fold in until only a few lumps remain and the flour is hydrated.
130 g All-purpose flour, 20 g Cornstarch
Transfer the ladyfinger batter to a piping bag with a large, round piping tip.
Pipe the ladyfingers into 3.5-4 inch logs on the prepared baking sheets, with a couple of inches in between each. You should be able to fit about 12 ladyfingers per baking sheet.
Dust the tops with a generous coating of powdered sugar.
Powdered sugar
Bake one sheet at a time for 13-15 minutes, or until the tops are crisp and the bottoms just start to turn golden brown.
Cool completely on a wire rack and bake the other sheet of ladyfingers.