Preheat the oven to 190°C/375°F/Gas mark 5
Put the molasses and sugar in a bowl. Add the butter to boiling water and when it is melted, add to the molasses. Add the sour cream and blend. Add the other ingredients and blend well. Let the mixture stand for one hour in a cold place so it will thicken
Drop by teaspoonful onto a greased baking tray. Leave room for expansion. Use a spoon dipped in milk to flatten cookies and make them shiny. Bake for 10-15 minutes. Cool on a wire rack.