Preheat the oven to 350°F(180°C). Line two baking sheets with parchment paper and set aside.
Add the all purpose flour to a mixing bowl and add cornstarch, baking powder, baking soda and salt and mix. Set aside.
To the bowl of your stand mixer, add the vegan butter, half of the white sugar, the vanilla extract and cream together until light and fluffy. Set aside.
In a separate stand mixer bowl with clean beaters, whip the aquafaba until white and frothy. Then, while beating, slowly add in the remaining sugar and beat for 5 minutes until thick and glossy.
Gently fold the aquafaba mixture, spoonful’s at a time, into the butter mixture until well combined, taking care not to deflate the mixture.
Sift the dry ingredients into the batter and fold until just combined.
Add the soy milk and mix until combined. The dough should be stiff but you should still be able to pipe it.
Transfer the dough to a piping bag fitted with a large round piping tip (ideally an Ateco 808 piping tip).*
Pipe 3.5 inch long (about 1 inch wide) ladyfingers onto the prepared baking sheet aiming for 18-20 ladyfingers.*
Dust one pan lightly with powdered sugar and bake at 350°F(180°C) for 15 minutes until lightly golden and firm to the touch.*
Dust the remaining baking sheet with powdered sugar and bake as directed.
Let the cookies cool completely before serving.