This dough chills overnight. On the day you're ready to bake, preheat oven to 400.
For the dark dough: sift together flour, salt, baking soda, cloves, and cinnamon and set aside.
Grind or cut chocolate until it is fine (otherwise it will be hard to slice the dough). Set aside.
In the large bowl of an electric mixer, cream the butter, add the coffee and brown sugar and beat well.
Add the eggs and beat to mix. Beat in the ground chocolate.
On low speed gradually add the sifted dry ingredients, scraping the bowl regularly. Don't overblend! Then stir in the nuts. Set the dough aside (not in the fridge) and make the light dough.
Light dough: Sift together flour, salt, baking soda. Set aside.
In a large clean bowl of the electric mixer with clean beaters, cream the butter. Add the vanilla, the sugar, water and beat well. Add the egg, beat to mix. On low speed gradually add the shifted dry ingredients. Don't overmix.
Mix in the currents, lemon rind and cherries.
Layer dough in the pans: one half the dark dough (carefully pack down and smooth), all the light dough (do the same), then the rest of the dark dough. Press down to make a compact loaf.
Chill overnight (or for about twelve hours) in the freezer.
To bake: preheat to 400. You'll need unbuttered cookie sheets, lined with foil if possible.
Turn the pan over so that the cake of dough slides out, and peel off the foil or waxpaper. With a long and heavy knife, cut the cake in half the long way (if you used loaf pans); if you used a square 8x8 pan, cut it in three equal strips. Work with one piece at a time (wrap and freeze the others). Now slice the long piece you've got into individual cookies, about 1/3 of an inch thick. Place them 1 1/2 inches apart on the cookie sheets - they will spread!
Bake 10 minutes, watching carefully. The white dough should be lightly browned, but the dark dough will burn if you're not careful. If they come out of the oven seeming slightly underdone, that's good. They'll be chewy instead of brittle.