Preheat the oven to 160C/325F/gas mark 3
Use a 20cm/8 inch deep round cake tin.
Grease the cake tin and line with greaseproof paper. In a large mixing bowl, beat together the butter and sugar until light and fluffy. Beat in the sour cream, a little at a time. Stir in the raisins and cherries, then the milk. Sift together the flour and spice and fold into the fruit mixture until evenly blended.
Roll out half the marzipan to a 20 cm/8 inch round. Place half the cake mixture in the prepared tin and cover with the round of marzipan. Spoon over the remaining cake mixture and smooth the surface. Bake for 2 1/4 hours, until the cake springs back. Leave to cool in the tin.
