Make pastry shell: in medium bowl, combine piecrust mix with brown sugar, walnuts and grated chocolate. Add 1 tablespoon. water and the vanilla. Using fork, mix until well blended. Turn into well buttered 23 cm pie plate; press firmly against bottom and sides of pie plate. Bake 15 minutes. Cool on wire rack. Make filling: in small bowl, with electric mixer at medium speed, beat the butter until it is creamy. Gradually add granulated sugar, beating until light. Blend in cool melted chocolate and 2 teaspoons instant coffee. Add 1 egg, beat 5 minutes. Add second egg, beat 5 minutes longer. Turn filling into baked pie shell. Refrigerate the pie, covered at least 8 hours, but best held overnight. Topping: Next day make topping. In large bowl, combine cream with 2 tablespoon instant coffee and the confectioners' sugar. Cover and refrigerate 1 hour. Beat the cream mixture until stiff. Decorate pie with topping using pastry bag with star or shell decorating tip, if desired. Garnish with chocolate curls. Refrigerate at least 2 hours.