In small bowl, stir together coffee crystals, water and vanilla
until coffee are dissolved. In a medium bowl, stir together flour
and cinnamon. In a large mixing bowl, beat butter or margarine
until softened. Add sugar and brown sugar and beat until fluffy.
Add egg yolk and coffee mixture, beat well. Gradually add flour
mixture,, beating until well mixed. Press evenly into an
ungreased 15x10x1 inch baking pan.
Bake in a 350 degree oven for 15-18 minutes or until done.
Immediately sprinkle chocolate pieces over top. Let stand until
chocolate is softened, then spread evenly. Sprinkle with nuts.
Cut into bars while warm, cool.