This cake came about when our German au pair told me how much she missed her mum’s poppy seed cake – so we decided to make it in Ireland. After a little bit of experimenting, we came up with this recipe. It is incredibly rich – one small slice generally suffices – and it is absolutely divine! This cake will keep for a few days but it can also be frozen un-iced.
Preheat the oven to 170ºC (325°F), Gas mark 3. Butter the sides of a 20cm (8in) diameter spring-form/loose-bottomed tin cake tin and line the base with greaseproof paper.
Cream the butter in a large bowl or in an electric food mixer until soft. Add the sugar and beat until the mixture is light and fluffy. Gradually add the beaten eggs, beating well between each addition.
Sift in the flour and baking powder, add the poppy seeds and stir until combined.
Spoon the mixture into the prepared cake tin, making a slight hollow in the centre with the back of a spoon. Bake in the oven for 25–28 minutes or until it is cooked in the centre and a skewer inserted into the middle comes out clean.
Allow the cake to stand for 5 minutes before carefully removing it from the tin and transferring it to a wire rack to cool.
Meanwhile, make the buttercream filling. Using an electric whisk, beat the butter until pale and soft, beat in the icing sugar and vanilla extract.
When the cake is cold, sandwich the layers together with the filling. If you wish, when the cake is cool, split it in half using a long-bladed serrated knife. Place one layer of the cake on a serving plate and spread over 2 generous tablespoons of the vanilla buttercream, then place the other half of the cake on top. Spread the remaining icing over the top and sides with a palette knife or table knife. The cake can also be kept whole, with the icing spread over the top and sides.