1 For the base layer: heat the oven to 180°C (160° fan) 350°F gas 4. Grease a 25cm|10: springform cake tin and line the base with non-stick baking paper.
2 Whisk together the butter, flour, icing sugar, baking powder, egg yolks and soured cream in a mixing bowl until well blended.
3 Put into the tin and spoon the jam evenly on top.
4 For the top layer: heat the milk and poppy seeds to a boil in a pan, stirring occasionally until all the milk is absorbed. Remove from the heat and leave to cool.
5 Whisk the egg whites until stiff but not dry.
6 Add the butter, sugar, flour, vanilla, orange zest and baking powder to the poppy seed mixture until well blended. Gently fold in the egg whites.
7 Pour the poppy seed mixture over the base and jam.
8 Bake for about 30 minutes until risen and cooked through.
9 Sift icing sugar over the top and arrange the apricot halves on top