Put sugar with 4 pint (U.S. If cups) water into a pan. Dissolve sugar on a low heat. When com¬pletely dissolved bring to the boil and boil for five minutes. Meanwhile mix the cornflour with the remaining water till smooth. Take the syrup off the heat and when it has stopped bubbling add the cornflour and return to the heat. Add colour¬ing (green, red or yellow are the traditional colours) and cook, stirring continuosly till the mixture soli¬difies. Mix in the lemon juice. Add the butter a little at a time, stirring all the time till all butter is absorbed. Keep on cooking till mixture separates from the side of the pan. Mix in the nuts and cardamoms. Spread in a shallow dish and flatten out with a knife. Cool and when completely set, cut into squares with a sharp knife.