Preheat the oven to 180 ° C
Cream the softened butter with the sugar then add the eggs. Mix.
Add all the other ingredients and mix until you get a smooth mixture.
Pour into a 20cm (8 inch) buttered mold.
Bake 40 Minutes at 180 ° C or until the sponge cake is golden and a clean knife comes out of it.
Once cooked, let the sponge cake cool, unmold and cut in half.
Spread the jam (the thickness of the jam depends on your desire) then put back the second part of the sponge cake on top.
Place in the fridge while you prepare the buttercream.
Mix all the ingredients together using an electric mixer until you get a creamy, blanched mixture.
Take the sponge cake out of the fridge then cover with buttercream.
Using a pastry bag, place dots of buttercream on top.
Add blueberries or other berries. Enjoy.