If you cannot buy nuts already ground, then grind them in a food processor, taking care not to overprocess them or they will turn oily; you can also process them with the sugar to prevent them from turning oily.
(Note if you are working with whole hazelnuts, toast them first in a 400 degree oven, rub off skins, let cool and then grind.) Combine the nuts with the butter, sugar and flour; you will have to combine this dough with your hands; if a bit too dry, add drops of lemon juice or rum. Form dough into a roll 1 1 /4inches thick. Refrigerate overnight in waxed paper or parchment.
Following day preheat the oven to 350 degrees. cut dough into 1 cm slices and bake on an ungreased cookie sheet for 15 minutes or until golden. Remove from oven and cool cookies on a rack.
When cooled to room temperature, sandwich two cookies together with raspberry jam and spread some of the chocolate icing (see below) over the top cookie. For a pretty presentation, set them in fluted paper cups.
CHOCOLATE ICING Melt chocolate with water and sugar. When melted, add instant coffee and cook over very low heat for 5 minutes. Turn heat off, add butter and let icing cool to room temperature. (Don't let it get too firm or it will be hard to spread over cookies.)