Preheat the oven to 180ºCGrease and flour two 20cm cake tins (or if you’re like me, use one tin and cut the cake in half—tricky!)
Mix the aquafaba with ground flaxseed and water to make the vegan 'eggs' (I like to use more than one type of vegan 'egg' so that it's more likely to do the job well)
Cream the vegan butter and sugar (or if you don’t have an electric mixer, beat the butter with a wooden spoon, then add the sugar, and beat with a whisk until fluffy).
Add the vegan eggs, and mix well.Mix the dry ingredients (flour, salt, baking powder) together.
Add the dry mix to the butter mixture, alternating with the milk, and mix until combined (don't over mix).
Pour into the prepared cake tins.
Cover one of the cakes with the prepared topping.
Bake for 25-30 minutes, then remove and place on a wire rack to cool thoroughly.
Meanwhile, prepare the filling: