We made this as the dessert for our Burns night supper. We swap the vodka Firean old reserve and the sugar syrup for honey syrup. For the top we used crushed up shortbread.
The trick is to hold a flat-ended bar spoon so the flat end is just over the surface of the bottom layer with the spoon's shaft pointing vertically up. Pour the second layer down the shaft of the spoon so the flat end dissipates the liquid over the bottom layer.