Ideally use a food-processor or mixer. Otherwise you need a spacious work-top, your two hands and a certain amount of courage.
Mix together, either on the working surface or in a bowl, the flour, ground almonds, grated lemon rind, sugar and a pinch of salt. Cut the butter into large cubes and put into a well in the centre of the flour, together with the whole egg, egg yolks and rum.
Work everything together lightly until you have a homogeneous paste, but do not overwork. Collect the pastry up into a mass and cut it into 12 pieces of 100 g (3½ oz) each, rolling each lightly into a ball. Enclose each one in a plastic bag and keep in the refrigerator or freezer until needed.