Preheat the oven to 160C/325F/gas mark 3
Use a 15cm/6 inch square cake tin.
Grease and line the cake tin. Sift the flour, salt, ginger and baking powder into a mixing bowl. Stir in the orange rind. Warm the butter with the sugar and syrup in a saucepan until the butter has melted but the mixture is not hot.
In a measuring jug, whisk the sour cream and add enough milk to make up to 125 ml/ 4 fl oz. Add the melted mixture to the dry ingredients with the whisked sour cream and milk mixture. Stir thoroughly. The mixture should run easily off the spoon. Pour into the prepared tin and bake for 1 1/4 - 1 1/2 hours until firm. Cool on a wire rack.
