Preheat the oven to 190C/375F/Gas mark 5
Cream the butter, sugar and sour cream until light and fluffy. Stir in the sifted dry ingredients and glace ginger. Mix well. Turn the dough onto a lightly floured surface, knead until well combined and cover. Refrigerate for 30 minutes.
Roll dough on a lightly floured surface until 4mm thick. Cut 5cm rounds from the dough. Place onto greased baking trays about 4cm apart. Bake for about 10 minutes or until lightly browned. Cool on trays.
Dip half of each cookie in the combined melted carob chips and butter. Stand on greaseproof paper until set. Makes about 30.
