Martha Collison's lemon & poppy seed cake

Preheat the oven to 180°C, gas mark 4, and grease and line two 20cm cake tins with baking parchment.

Using a handheld electric whisk or a stand mixer, cream together the butter and sugar until really light and fluffy. Add the eggs one at a time, whisking after each addition.

In a small bowl, combine the flour, baking powder and poppy seeds. Add these dry ingredients into the egg mixture a few tablespoons at a time, and continue to mix until a smooth batter forms. Add the lemon zest and milk, and mix again.

Divide the mixture between the two tins and use a spatula to smooth over the top. Bake for 25-30 minutes or until golden and well risen. A skewer, when inserted in the centre, should come out clean. Allow to cool briefly in the tins before turning onto a wire rack to cool completely.

To make the filling, beat together the mascarpone, double cream, lemon juice and icing sugar until smooth and spreadable. Place the bottom cake onto a stand and spread with the mascarpone icing. Spoon over the lemon curd and sandwich with the top layer of cake. Dust the top with icing sugar and serve.