Preheat the oven to 150°C, top and bottom heat.
In a tall jar, combine soy milk, vegetable oil, sugar, vanilla sugar and salt.
Blend with a hand blender for 30 seconds.
In a big bowl, sift flour, cocoa powder, cornstarch, and baking powder.
Add the liquids and whisk until the flour is fully incorporated but don’t overmix.
Pour the batter into a greased and lined cake pan or ring.
Bake at 150°C for 60 to 70 minutes.
Check the cake after 60 minutes with a wooden skewer. If there’s no liquid and just a few crumbs remain it’s ready to come out of the oven.
Allow the cake to cool completely at room temperature for at least two hours.
Wrap in clingfilm and refrigerate for four hours or best overnight.