Before we begin, preheat your oven to 200°c /180°c fan / gas mark 4. Grease and line the bases of 2 x 20cm cake tins.
Grab a large bowl. In it, beat together the butter and sugar until it’s light and fluffy.
Next add the eggs. A little at a time and beat well after each addition. If you find that the mixture curdles, add a little of the flour.
Fold in the remaining flour, baking powder then add your vanilla and lemon zest. Don’t worry if the mixture is too thick and does not fall off a spoon, just stir in a little milk.
Divide the mixture evenly between the two cake tins. Put the tins into the oven for 25 to 30 minutes or until a skewer comes out clean when inserted into the middle.
Next up, the lemon syrup. Place the lemon juice into a small bowl and stir in the sugar until it’s dissolved. Set aside for later.
When the cake is ready, take it out of the oven and place the tins onto a wire rack. Use a skewer to make holes in the top of each cake and pour over the lemon syrup. The holes will allow the syrup to seep in. Leave the cakes to cool then remove them from the tin.
Using your electric whisk or food processor, beat together the icing sugar and butter until light and creamy. Put this mixture into a large clean bowl and fold in the lemon curd to get a marbled effect.
The finale. Spread the icing over the top of one cake. Top with the other cake and spread over the remaining butter icing. Top with the blueberries and raspberries, and sprinkle with icing sugar to finish.
Now, dig in.