Preheat the oven to 180C/350F/gas mark 4
Use a 20cm/8 inch round cake tin.
Grease and base line the cake tin. Put the poppy seeds into a pan with the milk and bring to the boil. Set aside to cool completely. In a large mixing bowl, beat the butter and sugar together until pale and fluffy. Add the sour cream. Sift the flour into a bowl, adding any residue of bran left in the sieve. Fold the flour into the creamed mixture, then stir in the poppy seeds and milk. Spoon the mixture into the tin and level the surface.
Bake for about 1 hour, or until the cake has risen and browned and is beginning to shrink from the sides of the tin. Leave to firm up in the tin for 5 - 10 minutes, then turn out onto a wire tray. Peel off the lining paper and allow to cool.
