Preheat oven to 350. Combine the flour, salt and brown sugar. With a pastry blender or 2 knives, cut in the butter.
Stir in the chocolate and nuts. Mix the vanilla and water and add to the crumbs.
Work the mixture with your hands to combine. With floured fingers, push the mixture into a 9 inch pie plate, covering the bottom, sides and rim. Bake for 20 minutes. Cool completely.
In an electric mixer, cream the butter till fluffy and smooth. Add the sugar, coffee and vanilla and beat till smooth. Add the melted chocolate. Again beat smooth.
Add the eggs one by one, beating for several minutes after each addition.
(NOTE: If you prefer to cook the eggs first, mix them with 1/4 cup milk and heat over medium low heat, till the mixture thickens and bubbles a bit, and coats a spoon -reaching a temperature of 160. Cool and add to the chocolate mixture.).
Spread the mixture into the pie crust. Chill several hours. (At this point, the pie can be wrapped and frozen. Defrost in the refrigerator for 6-8 hours.).
Just before serving, whip together the cream, coffee, powdered sugar, cocoa and vanilla till stiff enough to hold a shape. Cover the top of the pie and top with grated chocolate, if desired.