Preheat the oven to 180C/350F/gas mark 4
Use a 20cm/8 inch round cake tin.
Grease and line the cake tin. Place the butter in a saucepan and melt over a very low heat. Pour the melted butter into a large mixing bowl and add sugar, carrot, salt, cinnamon, nutmeg and sour cream. Sift the flour and baking powder into the bowl and add raisins and walnuts, fold in thoroughly with the milk. Spoon the mixture into the prepared tin and bake for about an hour until firm to touch. Cool in tin for 10 minutes then transfer to wire rack to cool completely.
