Preheat the oven to 180°C. Cream butter and Chelsea Soft Brown Sugar together, then beat in the egg. Add all the dry ingredients to the butter mixture and, using a spoon, mix it until combined.
Roll out dough on a lightly floured surface then cut out circles (make sure you have an even number!). Place on a cold greased tray and bake them for 15-20 minutes. When brown, take out of oven and leave to cool on a wire rack. When the biscuits are cold, sandwich them together with raspberry jam.
Boil the jug, put about 1/4 - 1/2 a cup of icing sugar in a bowl and then add a tiny amount of hot water. Don't put too much otherwise it will be runny! Add enough hot water for it to be spreadable.
Put the icing on the top of the biscuits and sprinkle with jelly crystals or hundreds and thousands.