Make the chai sponge cakeGrease and flour three 15cm/6-inch round cake pans.
In a small bowl, pour in the milk and apple cider vinegar. Set aside for 10 minutes.
In a medium bowl, whisk together the flour, cinnamon, cardamom, baking powder, baking soda, ginger, nutmeg, cloves, and salt.
In a bowl of a food processor, add sugar and softened coconut oil. Beat until fluffy, 1 minute. Add the milk and vanilla; beat on low speed until well-incorporated.
Pour the dry ingredients into the wet ingredients and fold gently until just combined. Do not over-mix. Divide the batter among the 3 prepared cake pans.
Bake at 180C degrees for 25 minutes or until a skewer comes out clean. The sponges will be lightly browned and beginning to pull away from the sides.
Remove and cool 10 minutes before turning the cakes onto a wire rack to cool completely.
Make the blackberry jam Add the blackberries, agave and lemon juice to a medium size pot set over high heat.
Bring the mixture to a boil, once boiling use a potato masher or fork to break down and mash the berries.
Continue to cook for 10 minutes or until the jam has reduced and thickened by 1/3. Remove from the heat and let cool.
Make the buttercreamIn a food processor, combine all the ingredients and slowly beat until fluffy. Don’t over mix.
Assemble the cakePlace one cake layer on a serving plate. Spread 1/3 of the buttercream over the cake and layer with about 2 tbsp of jam. Repeat with the remaining cake layers.
Be careful not to over fill your layers or the cake will be hard to slice.
Lightly frost the outside of the cake. Chill 30 minutes.
Serve or store in the fridge for up to 3 days.