In the meantime, it is time to prepare your stock. I find the jelly stock pots perfect for this, so chuck your stock cube into a measuring jug and add the water. Then add the chilli, ginger, garlic and lemongrass. With the lemongrass it is important to bash it with the flat part of a knife before you add it, as this releases all of the flavour. Set this aside to let all of the flavours infuse.