Beat together the butter, caster sugar and vanilla essence until light and creamy.
Add the egg and beat well. Add the jam and beat again until smooth.
Fold in sifted flours, bicarbonate of soda and cocoa alternately with the buttermilk until nice and smooth.
Spoon the mixture into cupcake cases and bake for 20 minutes or until a skewer comes out clean when inserted in the centre. Leave cakes to cool completely before decorating.
Whip cream and icing sugar together until thick. Pipe cream onto cakes and decorate with fresh raspberries and raspberry sauce.
I served these cupcakes in edible chocolate cases which I made by melting chocolate and coating silicone moulds before placing in the freezer to set. Once set, peel off the moulds and keep in the refrigerator until ready to serve.I made the raspberry sauce by blitzing fresh raspberries with a touch of lemon juice and icing sugar to taste and then passing through a sieve to remove any seeds.