Combine chocolate wafer crumbs and 1/3 cup melted butter; firmly press on bottom and sides of a 9-inch tart pan or pie plate. Bake at 350°F for 6 to 8 minutes.
Cream 1/2 cup softened butter; gradually add brown sugar with the electric mixer at medium speed until blended. Add the eggs, one at a time, beating after each addition. Stir in the melted chocolate, instant coffee granules, vanilla extract, flour and chopped pecans.
Pour into the prepared crust. Bake at 375°F for 25 minutes. Remove from oven and cool completely on a rack.
Before serving, pipe sweetened whipped cream on each piece and drizzle With chocolate syrup. Garnish with cherries and/or mint if desired.