Split the vanilla bean down its length huh b the paring knife. Scrape out the seeds. Set aside.
In a large mixing bowl, combine sugar, butter, lemon, milk, and vanilla bean. Then whisk in almond flour, all purpose flour, cornflour, baking powder, salt. Gently mix until just combined. Refrigerate the batter at least 20 minutes until batter is thicken.
Lightly coat your Madeleine pan with vegan butter. Scoop batter into moulds using a mini ice cream scoop, about 1 1/2 scoops. Bake at preheated oven 180 celsius for 25 minutes or until edges begin to become a little golden.
Remove pan from the oven. Allow to cool slightly and remove from the tin and allow to cool. Once cooled completely and dust with powdered sugar and serve!