Preheat oven to 180•c and grease 2 6 inch cake pans. Grease tins thoroughly. Line the base with parchment paper and grease the paper too.
In a large bowl, whisk together plain flour, baking powder, baking soda and salt. In a stand mixer or using an electric whisk, beat sugar and butter together until smooth and creamy, about 2-3 minutes.
Prepare flax eggs in a small bowl by mixing flax and water together to form a gel. In a jug, add soya milk and apple cider vinegar, stir well and set aside to thicken for a few minutes, this will form a vegan buttermilk.
Add dry ingredients to the creamed butter and sugar and mix on low until just combined. Add flax eggs and vegan buttermilk and slowly mix until combined. Pour evenly into cake pans and bake for 23-25 minutes, until a toothpick comes out clean. Allow cakes to cool completely in the pans on a wire rack. To prepare the buttercream, add vegan butter to a stand mixer or with an electric whisk beat until creamy, around 3 minutes. Add icing sugar, 2 tbsp of the soya milk and vanilla extract. Mix on a medium speed for another 3 minutes, adding the remaining soya milk if it’s too thick.
Layer cake up with vanilla buttercream, raspberry jam and pipe remaining frosting on top. Top with fresh raspberries and a dusting of icing sugar. Chill in the fridge for half an hour before slicing. Leftover cake can be stored in the fridge for up to 4 days.
