Preheat your oven to 180c and line a cupcake tray with paper cases.
In a mixing bowl, cream together the vegan butter and sugar until light and fluffy. Then whisk In the milk and vinegar mixture and vanilla.
Fold through your dry ingredients to create a smooth batter. Using an ice cream or cookie scoop, divide the mixture amongst the cases for an even result.
Add a few pieces of chopped plum into the centre of each cake and bake these for approximately 25 minutes.
Once your cakes are cooked through and golden in colour, allow to cool completely on a wire wrack.
Meanwhile, beat your vegan butter until pale, then gradually incorporate the icing sugar. Mash your blackberries and berry powder (if using) into your butter cream. You can add extra icing sugar to thicken if required.
Pipe or spread the frosting onto each of your cakes and garnish with toppings of choice!
